Brown Butter Salted Caramel Slice - a toasty brown butter shortbread is topped with a chewy, silky brown butter caramel, and finished off with a smooth layer of chocolate. This is a slight twist on the classic bakery treat, and is sure to become a firm favourite.
Hi! I hope you are staying safe! I’ve been hanging out at home, doing all of the puzzles and bopping around in my tiny NYC kitchen making all sorts of things - most recently, this brown butter salted caramel slice! There’s a brown butter shortbread base, a super chewy, silky brown butter caramel filling, and then a smooth chocolate topping to finish it all off, complete with some retro bakery style feathering if you feel like fancying it up a little bit (it’s easy and I’ll tell you all about it, I promise!).
I grew up eating caramel slice, or millionaire’s shortbread as I think it is called here in the states - it is a New Zealand bakery staple, and one of my favourite things. It varies from place to place in both the ratio of base to caramel, and also in the technique of the caramel. Some recipes will have you stir together a filling and then pop it in the oven to finish, but others will have you make a caramel on the stove top and pour it over the cooled shortbread base to set. I went for the stovetop method as I feel it is much easier to control and you know when it is done by using a thermometer to measure the temperature of the mixture.
I browned the butter for both the shortbread base and the caramel filling, which gives this a super toasty, extra delicious flavour. Browning butter is great because it adds so much flavour wise, without having to use any extra ingredients. The shortbread is super simple and I actually found it easiest to make it by hand rather than using a mixer, and just using a spatula instead to bring the base together. I creamed brown butter which I had chilled back down to be spreadable with some brown sugar, then added in some flour, vanilla and salt, to make a super smooth shortbread base which is insanely satisfying to pat into your baking pan. The shortbread base gets baked until it is nice and toasty, then once it is cool it is caramel time!
The caramel filling is perfectly thick and chewy, and has a lovely silkiness to it, which is thanks to the Eagle Brand® Sweetened Condensed Milk that I used! I love all things condensed milk. It is perfect to have on hand for times like this when you just need a little caramel slice treat, and Eagle Brand is super simple - it’s only ingredients are milk and sugar! I started with the condensed milk and brown butter as a base, then added in some golden syrup for texture (set caramel benefits from an invert sugar), a little bit of brown sugar for colour and toastiness to help bring out the brown butter flavour, and a solid dose of salt.
I finished it off with a thin layer of dark chocolate, which I added a wee feather texture to by drizzling some white chocolate over the surface and feathering it using a cake tester. This is a totally optional step but it’s super easy and makes the caramel slice look a little fancy. You could also sprinkle a little flaky sea salt on the top of the chocolate topping instead of the feathering - you do you here!
A few wee tips:
I am going to get you to brown all of the butter at once, so that you don’t have to do the process twice. You want to brown it and then place into a bowl or container and chill it down until it is a spreadable texture - either you can do this in the freezer, stirring often, or if you are making it ahead, just pop it in the fridge then bring out and let it come to a spreadable texture when you are ready to bake.
You will notice that the quantity of butter needed is more than the quantity of brown butter that I call for in the recipe. When you cook brown butter, it loses volume from cooking out the water during the browning process, so the initial quantity of butter reflects the amount lost during the browning. I added just a touch more as a buffer so you’re not caught short!
The brown butter for the caramel filling can be fridge solid and you can just plop it in - it will get melted so don’t worry about bringing that to room temp!
I used golden syrup in the filling, but honey or corn syrup will work well too!
The caramel needs to set for an hour and a half or two hours - I like to assemble it all and then set it overnight or for at least 3 hours just to make sure that it is all set.
If you don’t want to brown the butter you can use the same amounts of unsalted butter.
Adjust the salt content to what works for you!
I like to use little bulldog clips to hold my parchment to my pan edges. If you get the unpainted ones they are fine to go in the oven.
Thank you so much to Eagle Brand® Sweetened Condensed Milk for sponsoring this post. All opinions are my own.
Toasty brown butter shortbread is topped with a chewy, silky brown butter caramel, and finished off with a smooth layer of chocolate.
- 360g unsalted butter, cold from the fridge is fine
Brown Butter Shortbread Base
- 160g brown butter, at room temperature, spreadable consistency (see notes)
- 85g dark brown or light brown sugar
- 1/2 tsp kosher salt
- 3/4 tsp vanilla bean paste or vanilla extract
- 275g all-purpose flour
Brown Butter Salted Caramel Filling
- 1 14oz (400g) can Eagle Brand® Sweetened Condensed Milk
- 185g dark brown or light brown sugar
- 100g brown butter
- 50g golden syrup or corn syrup
- 3/4 tsp kosher salt (drop to 1/2 tsp if you don’t like your caramel super salty)
- 1/2 tsp vanilla bean paste
- 180g dark chocolate
- 30g neutral flavoured oil
- Optional for feathering - 50g white chocolate melted with 1/2 tsp neutral flavoured oil
- Place the butter in a medium saucepan, and place over medium heat. Cook until the butter has melted, and then continue to cook, swirling the pan often, until the butter foams and turns golden brown and nutty - this should take 3-4 minutes.
- Transfer to a bowl, allow to cool slightly, then transfer the bowl to the freezer and chill the butter until solid. Remove from the freezer and bring to room temperature, stirring often, until soft and spreadable.
BROWN BUTTER SHORTBREAD BASE
- Preheat the oven to 325°f / 165°c. Grease an 8” (20cm) square pan and line with two pieces of parchment paper that extend over the sides of the pan to use as handles.
- In a medium bowl, cream together the spreadable brown butter and brown sugar using a spoon or spatula. Add the salt, vanilla, and flour, and bring together to form a soft, homogenous dough. Pat the dough into the bottom of the prepared pan, smoothing down with a flat bottomed measuring cup or offset spatula. Prick all over and chill for 10 minutes.
- Bake the base for 30 to 35 minutes, until set and evenly golden. Remove from the oven and allow to cool completely.
BROWN BUTTER SALTED CARAMEL FILLING
- Place the Eagle Brand® Sweetened Condensed Milk, brown sugar, brown butter and golden syrup in a medium sized heavy bottomed saucepan.
- Place over a medium heat and stir until melted together, then cook, stirring constantly with a whisk or rubber spatula (I like to use a whisk then switch to the rubber spatula), until the mixture registers 220°f / 105°c on a candy thermometer. Watch the bottom carefully to avoid the mixture catching, turning down the heat if needed.
- Once the caramel has reached the correct temperature, add the vanilla and salt, mix well to incorporate, and pour it over the cooled shortbread base and smooth off by shaking the pan and using an offset spatula if needed. Transfer to the fridge and allow to set for 1 to 1 1/2 hours or until you can no longer feel heat in it.
- In a heat proof bowl set over a pot of simmering water, melt together the chocolate and the oil, stirring frequently, until smooth. Alternatively, melt together in the microwave in 30 second increments, stirring well after each.
- Pour over the set caramel filling, and tilt the pan to evenly coat. Bang the pan on the counter several times to smooth out the topping and eliminate any bubbles. If you would like to add the feathering, pipe horizontal stripes of the melted white chocolate across the surface, then feather using a skewer by dragging it up and down the surface of the chocolate, perpendicular to the lines that you piped.
- Chill in the fridge until completely set, at least an hour or up to overnight. Remove from the pan by using the parchment paper slings. cut into slices using a sharp knife, wiping between each. Store in an airtight container.
Keywords: Caramel Slice, Brown Butter, Salted Caramel, Millionaire's Shortbread