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.

Table of contents
- Birthday Cake Blondies
- What are Blondies?
- Even Better Brownies by Mike Johnson
- Ingredients in Birthday Cake Blondies
- How to Scale a Recipe
- FAQ for Birthday Cake Blondies
- A few wee tips for Birthday Cake Blondies
- For more Bar recipes, check out:
- Made this recipe and love it?
- A note on salt and oven temperature
- Why is this recipe in grams?
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.
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!
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.
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.
FAQ for Birthday Cake 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!
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.
These are great made ahead of time! Once they are cool, pop them into an airtight container.
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!
For more Bar recipes, check out:
Made this recipe and love it?
I would LOVE for you to leave me a review below to let me know how you liked it! Make sure to tag me on Instagram if you make it!
A note on salt and oven temperature
It is important to note the type of salt that is called for in a recipe. I use Diamond Crystal salt throughout my recipes - if you use a different sort of kosher salt or regular table salt you will need to adjust accordingly as some salt is 'saltier' than others. Morton's salt is twice as salty, so you will need half the quantity. Same goes for a regular table salt. I am working to get gram measurements throughout my recipes for salt but still getting there.
All oven temperatures are conventional unless otherwise stated. If you are baking on fan, you will need to adjust the temperature. An oven thermometer is a great investment to ensure that your oven is the correct temperature.
Why is this recipe in grams?
I post my recipes in grams as it is the most accurate way to bake. Cups are not only inaccurate but they vary in volume worldwide. There is no way for me to provide one cup measure that works for everyone. However, posting in weight fixes this issue. If you would like the recipe in cups you are welcome to convert it yourself via google, but please do not ask me to do it for you as I am not comfortable providing a recipe using a method that I have not tested. Baking with a scale is easy, accurate, and also makes cleanup super simple. Here is the scale that I use if you would like a recommendation! Here's to accurate baking!
PrintBirthday Cake Blondies
- Prep Time: 15 minutes
- Cook Time: 35 minutes
- Total Time: 50 minutes
- Yield: 16 Bars 1x
- Category: Blondies
- Cuisine: American
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
- 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 tsp for the top
- 90g white chocolate chips
Instructions
- 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.
- In a medium bowl, combine the flour, salt, and baking powder. Set aside.
- 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.
- Gently fold in the sprinkles and the white chocolate chips until evenly incorporated. Transfer the batter to the pan and top with the 1 tsp rainbow sprinkles.
- 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.
- 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
Keywords: Blondies, Birthday Cake Blondies, Funfetti Blondies, Sprinkle Blondies
Comments
can't wait to try these!!
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Erin!!! This is the sweetest post ever and these photos came out BEAUTIFULLY 😍
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Awwww thanks for writing the best book! <3
I regret making this only for one batch. Made it yesterday and all I have now is just crumbs.
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Hahahah yayyyyy! SO good right x
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!
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These are so yummy! The perfect amount of vanillay sweetness and smelled amazing while baking!
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Ahhh I am so happy you loved!
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 🤗
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So happy you loved!
Honestly the best blondie recipe I've ever had! They turned out perfect!
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Ahhh so happy you loved! Mike's book is full of incredible recipes if you need more!
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.
★★★★★
Ahhh it's such a good recipe! Thanks so much for leaving a review - I appreciate it so much!
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!
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I have made this recipe 4 times in the past 3 weeks, it's SUCH a hit!
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Ahh yay!
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 🙂
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Yayyy oooh I bet it's so good with the m&ms too!
I’m eager to make the holiday version! Any idea of cook time for a doubled 9 by 13 pan? Thanks!
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Probably not too different if the thickness of the blondie is the same 🙂
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!
★★★★
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
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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.
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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!
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