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    Home » Recipes » Bars and Slices

    Birthday Cake Blondies

    By Erin Clarkson on Dec 13, 2020 (updated Dec 1, 2024)
    5 from 21 reviews
    31 community comments
    This post may contain affiliate links.

    Jump to Recipe

    These soft and chewy Birthday Cake Blondies are filled with sprinkles and white chocolate chips. These Blondies are super easy to make and come together quickly, and are stuffed full of nostalgia.

    Top down bite shot of birthday cake blondies

    Birthday Cake Blondies

    Hi! Just popping in here to share this new recipe with you from my friend Mike's book - Birthday Cake Blondies! These blondies are buttery, soft, and chewy, and are filled with rainbow sprinkles and white chocolate chips. They come together super quickly so are perfect if you need to throw something together to have in a pinch, or they are the best quick baking project if you are in need of something sweet.

    • side on stack shot of birthday cake blondies
    • corner shot birthday cake blondies

    What are Blondies?

    I'm not going to lie - I hadn't heard of blondies until I moved to the States, and even then I wasn't super familiar with them for a while! This is the first blondie recipe on the site but it certainly won't be the last, as I am totally hooked on how good they are. Blondies are basically the sister to brownies, but instead of being flavoured with chocolate and cocoa like brownies, they are vanilla flavoured! They still have all the good stuff brownies have - white and brown sugar, some oil, melted butter, egg, etc, but just minus the cocoa and melted chocolate. Mike amped it up one more step by adding in sprinkles and white chocolate for a nostalgic Birthday Cake situation. 

    Even Better Brownies by Mike Johnson

    This recipe for Birthday Cake Blondies comes from one of my best baking buddies, Mike! Mike runs the amazing blog MikebakesNYC, and is a super close friend of mine - we spend most work days texting back and forth with ideas and recipes, bouncing things off each other and cheering each other on. It's the best sort of friend to have and I am so grateful for our friendship, and just SO proud of his new book, Even Better Brownies!

    Mike's book is full of Brownie and Bar recipes, and is a must-own. He covers basically everything you can think of - there's cookie bars and blondies, a small batch brownie recipe, ice cream sandwich recipes, cheesecake, you name it. It's going to be a go-to book for me whenever I need brownie or bar recipe inspiration, and because it's Mike, each recipe is accompanied by the most beautiful photos. He also wrote it in a super short time period while working a FULL TIME JOB as a lawyer on the side. Just casually. The guy is amazing. Congrats Mike! I am so, so proud!

    • side shot birthday cake blondies
    • Bite shot of birthday cake blondies

    Ingredients in Birthday Cake Blondies

    Blondies are essentially brownies but without the chocolate - so the ingredient list is super similar!

    • Brown and White Sugar - Brown sugar gives fudginess to brownies, while white sugar provides chew. Both essential for blondies!
    • Melted Butter - Butter provides flavour and lift in these brownies, and helps the vanilla flavour to shine through.
    • Eggs - The blondies have that beautiful, crackly shiny top that you often see on brownies - this comes from beating the eggs together with the sugar until they are lightened in colour and have thickened. This aeration when baked up gives a paper thin finish to the blondie which is just so good!
    • Flour - Flour and baking powder give texture
    • Sprinkles and White Chocolate Chips - It wouldn't be birthday cake blondies without sprinkles! I used rainbow jimmies. Mike also popped some white chocolate chips in there for a super nostalgic vibe.
    • Vanilla - Mike calls for Imitation vanilla in this recipe, but I don't have any, so I subbed in some regular vanilla extract instead. Clear imitation vanilla will give you that real box mix birthday cake flavour if you're into that.
    side bite shot blondies

    How to Scale a Recipe

    Recipes that are made by weight can be easily doubled - the tricky part is working out what sized pan to use. The way that I work it out is like this - you work out the surface area of the pan that you are baking in (In this case 8"x8"=64 square inches), so for example a 9"x13" pan would have an area of 117 square inches, which is almost double 64, so if you doubled this recipe, baking it in a 9"x13" pan would work well. You would have to adjust the baking time slightly, but for pan conversion, this formula works well.

    • top down shot of birthday cake blondies
    • side on shot of blondie square

    Frequently Asked Questions for Birthday Cake Blondies

    What sort of sprinkles should I use for these blondies?
    Use Jimmies! The long, thin, waxy sprinkles. Don't use Non-pareils as they will bleed into the batter. Jimmies hold their shape when baking. Confetti sprinkles would work well too!

    Do I need an electric mixer for these?
    You don't! You should be fine with just a whisk. Just make sure that you mix the eggs and sugar together well until thick and lightened in colour.

    Can these be made ahead of time?
    These are great made ahead of time! Once they are cool, pop them into an airtight container.

    corner shot birthday cake blondies

    A few wee tips for Birthday Cake Blondies

    • Watch carefully when baking these - the line between underbaked and overbaked is quite thin. Check them after 30 minutes and give them an extra 2-3 if you think that they need it. You are looking for them to be golden brown and set on the top and edges.
    • Mike mentions putting half the chocolate chips on the top of the blondies before baking, but I folded them in instead and just added a few sprinkles on the top so that the chocolate didn't get too brown.
    • Mike calls for clear imitation vanilla in this recipe to get that real birthday cake vibe. I'm going to admit I'm not super into that, but if you are, then use the imitation stuff! I just used regular vanilla extract!
    Even better brownies by Mike Johnson

    For more Bar recipes, check out:

    • Black Cocoa Brownies with Oreo German Buttercream
    • Brown Butter Salted Caramel Slice
    • No-Bake Peppermint Slice
    • Peanut Butter Caramel Cheesecake Brownies

    ❤️ Made this recipe and love it? ❤️

    I would LOVE for you to leave me a review and star rating below to let me know how you liked it! Also, please make sure to tag me on Instagram!

    Answers to your baking questions

    Over the years, many of you have asked me questions about:

    • baking in grams
    • adjusting oven temperatures
    • what kind of salt to use
    • and many more!

    I've curated and answered them all for your easy reference in this frequently asked questions post!

    Print
    clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon
    top down blondies photo

    Birthday Cake Blondies

    5 Stars 4 Stars 3 Stars 2 Stars 1 Star 5 from 21 reviews
    • Author: Erin Clarkson
    • Prep Time: 15 minutes
    • Cook Time: 35 minutes
    • Total Time: 50 minutes
    • Yield: 16 Bars 1x
    • Category: Blondies
    • Cuisine: American
    Print Recipe
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    Description

    These soft and chewy Birthday Cake Blondies are filled with sprinkles and white chocolate chips. These Blondies are super easy to make and come together quickly, and are stuffed full of nostalgia.


    Ingredients

    Scale
    • 180g All-Purpose Flour
    • ½ tsp kosher salt
    • 1 tsp baking powder
    • 115g unsalted butter, melted
    • 165g dark brown sugar
    • 100g granulated sugar
    • 2 large eggs, at room temperature
    • 1 Tbsp vanilla extract
    • 4 Tbsp rainbow sprinkles, plus 1 teaspoon for the top
    • 90g white chocolate chips


    Instructions

    1. Preheat the oven to 350°f / 180°c. Grease an 8"x8" (20cm x 20cm) square cake pan and then line with parchment paper, leaving an overhang on all sides. Grease the parchment paper then set aside. 
    2. In a medium bowl, combine the flour, salt, and baking powder. Set aside. 
    3. In a large bowl, whisk the melted butter, dark brown sugar, and granulated sugar together for about a minute. Add the eggs and vanilla and beat until lighter in colour, about 4 minutes (I used a handheld electric mixer). Gradually add the dry ingredients to the wet ingredients and mix until just combined. 
    4. Gently fold in the sprinkles and the white chocolate chips until evenly incorporated. Transfer the batter to the pan and top with the 1 teaspoon rainbow sprinkles. 
    5. Bake until the top and edges are set and golden, 30 to 35 minutes. Remove from the oven and allow the blondies to cool in the pan for 45 minutes before removing and slicing. 
    6. Cover and store leftover blondies in an airtight container at room temperature for 2 to 3 days. 

    Notes

    Recipe reprinted with permission from "Even Better Brownies" by Mike Johnson

    Did you make this recipe?

    Tag @cloudykitchen on Instagram and use the hashtag #cloudykitchen

    Key Ingredients

    • Sprinkles
    • Vanilla
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    Filed Under: Bars and Slices, Brownies

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      Comments

    1. stacy says

      December 13, 2020 at 6:03 pm

      can't wait to try these!!

      Reply
    2. Mike Johnson says

      December 14, 2020 at 4:09 pm

      Erin!!! This is the sweetest post ever and these photos came out BEAUTIFULLY 😍

      Reply
      • Erin says

        December 14, 2020 at 8:51 pm

        Awwww thanks for writing the best book! <3

        Reply
    3. E says

      December 25, 2020 at 5:49 am

      I regret making this only for one batch. Made it yesterday and all I have now is just crumbs.

      Reply
      • Erin says

        December 25, 2020 at 9:04 am

        Hahahah yayyyyy! SO good right x

        Reply
    4. Alisha says

      April 09, 2021 at 3:40 pm

      was looking for a solid blondie recipe, and since I always have great success with everything Cloudy Kitchen I gave these a try. They were PERFECT! I usually struggle with a too-gooey/underdone blondie but this gave the perfect lift, chew and yes still some yummy fudgy texture. I did add one experimental ingredient: MALTED MILK POWDER and woah! used 4 tablespoons (don't have the grams on this, sorry!) and the depth of flavor was incredible. Thank you Erin!

      Reply
    5. Margaret says

      April 22, 2021 at 9:18 pm

      These are so yummy! The perfect amount of vanillay sweetness and smelled amazing while baking!

      Reply
      • Erin says

        April 23, 2021 at 12:35 pm

        Ahhh I am so happy you loved!

        Reply
    6. Alanna Green says

      May 08, 2021 at 7:55 pm

      Such an easy recipe to follow for such amazing tasting, chewy, fudgey blondies! Loved them. Waiting 45 minutes while they cooled was the hardest part in our house 🤗

      Reply
      • Erin says

        May 08, 2021 at 11:47 pm

        So happy you loved!

        Reply
    7. Kaitlyn says

      August 17, 2021 at 4:45 pm

      Honestly the best blondie recipe I've ever had! They turned out perfect!

      Reply
      • Erin says

        August 18, 2021 at 6:14 pm

        Ahhh so happy you loved! Mike's book is full of incredible recipes if you need more!

        Reply
    8. Taryn says

      August 17, 2021 at 11:32 pm

      I made a half batch of these (because I only had one egg left), used some chopped caramilk and left out the sprinkles. Turned out great! I just halved everything (except the chocolate!) lowered the oven temp to 160C, baked for 25mins in a 6x6inch pan. Yielded 6 perfect rectangle slices! Enough to satisfy a craving but not too much for me to feel like glutton eating them all week.

      Reply
      • Erin says

        August 18, 2021 at 6:15 pm

        Ahhh it's such a good recipe! Thanks so much for leaving a review - I appreciate it so much!

        Reply
    9. Sophie Warren says

      August 30, 2021 at 2:46 am

      these blondies are delicious! i made the true recipe once, then the next time i made the dough recipe and added dark chocolate and pistachios. my boyfriend and i can’t stop eating them!

      Reply
    10. Leilani says

      November 07, 2021 at 7:48 pm

      I have made this recipe 4 times in the past 3 weeks, it's SUCH a hit!

      Reply
      • Erin Clarkson says

        November 12, 2021 at 4:28 pm

        Ahh yay!

        Reply
    11. Aliyah says

      November 29, 2021 at 3:57 pm

      Foolproof recipe! I love this recipe. Have made blondies twice using it and both times, they’ve turned out fantastic and were well received by friends and colleagues both times. Fudgy, chewy and moorish!! I also added M&Ms for a lil crunch and they were a hit. Thank you 🙂

      Reply
      • Erin Clarkson says

        November 29, 2021 at 4:32 pm

        Yayyy oooh I bet it's so good with the m&ms too!

        Reply
    12. Adrianne says

      December 05, 2021 at 9:49 am

      I’m eager to make the holiday version! Any idea of cook time for a doubled 9 by 13 pan? Thanks!

      Reply
      • Erin Clarkson says

        December 06, 2021 at 9:41 pm

        Probably not too different if the thickness of the blondie is the same 🙂

        Reply
    13. Miriam says

      April 29, 2023 at 6:31 am

      Hi Erin!
      Made these twice now (once with fan and once with convection oven) and the flavor is phenomenal! However the do sink a lot when cooling which basically makes it a blondie cookie (still delicious!).. do you have any tips? Could it be because of Dutch sugar (which had molasses in it) instead of ‘american/NZ brown sugar?
      Thanks and keep up with the amazing you make!
      Miriam
      Ps good luck with the renovation!

      Reply
    14. Maris says

      May 03, 2023 at 11:05 pm

      Made just a few minor adjustments to the recipe and oh my gosh these were amazing! I have high expectations when baking and these somehow exceeded them! I made these for school. I brought 5 different treats on 5 different days and these were definitely everyone's favorite one that I brought. Would 100% make again

      Reply
    15. Maria says

      July 03, 2023 at 3:09 pm

      Super simple to put together and very yummy. I didn't have white chocolate, so I left it out. Used red, white and blue sprinkles to make it a July 4th holiday treat.

      Reply
    16. Andrea says

      August 06, 2023 at 5:28 pm

      Everything in this blog is worth trying. I've loved every single thing I've tried!!! Thanks for amazing recipes, and the best of all... in grams! I am trying right now not to eat all the blondies, they are the best I've made ever! I had some brown butter so I subs it for the melted butter and used biscoff cookies instead of the sprinkles... so so good! Thanks again Erin!

      Reply
    17. Jo says

      November 24, 2023 at 7:56 pm

      These are such a hit! Especially with the kids. Will make them again.

      Reply
    18. Deanna says

      April 06, 2024 at 6:22 pm

      Thank you for giving measurements in grams. It’s so hard to find good recipes in grams when I use google

      Reply
    19. Juliana says

      December 19, 2024 at 2:52 am

      This is a great birthday cake alternative!
      I made this for a friend who doesn't like chocolate (don't ask...) and she LOVED it!
      The buttery flavor is just to die for... and the confetti makes it so pretty to just look at!
      This is going into my Xmas treat box this year! 😉

      Reply
    20. Nina says

      February 03, 2025 at 12:46 pm

      Made these for husband's birthday, he deemed he liked these even more than the homemade funfetti cake he usually requests for his birthday! Said this may need to be the new birthday tradition! The whole family loved them and enjoyed with ice cream on the side. Used imitation vanilla to boost the birthday cake flavor and may even add a little more than a tablespoon next time! Thanks for sharing this recipe!

      Reply
    21. Anna says

      June 12, 2025 at 5:05 pm

      Yummmmmmmm
      I swapped sprinkles with raspberries.
      Turned out really good, although I baked a few mins too long! (Not your recipes fault, purely mine!) they are really tasty still though!

      Reply
    22. Rae says

      March 28, 2026 at 3:04 am

      We love this blondie, a solid fave in our house and workplaces ✨

      Reply
    Erin Clarkson Cloudy Kitchen

    HI, I'M ERIN

    My recipes range from quick & easy all the way to complex & impressive. I love the science and process of recipe development almost as much as baking itself. I specialize in rigorously tested recipes that are fun, reliable, and accurate.

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