Name: Milk Bar Birthday Cake
Prep time: 30 min
Cook time: 40 min
Total time: 70 min
Ingredients: 230 grams unsalted butter, softened; 200 grams caster sugar or granulated sugar; 2 teaspoons vanilla extract; 3 large eggs, at room temperature; 315 grams plain flour or all-purpose flour, sifted; 3 teaspoons baking powder; 1 pinch salt; 240 ml full fat or whole milk, at room temperature; 60 ml full fat Greek yogurt or sour cream, at room temperature; 50 grams funfetti sprinkles, rainbow jimmies (for celebration); 105 grams plain flour or all-purpose flour; 50 grams caster sugar; 1 tablespoon cornflour or corn starch; 1 teaspoon vanilla extract; 60 grams butter, melted; 3 tablespoons funfetti sprinkles; 230 grams butter, room temperature, roughly chopped; 2 teaspoons vanilla extract; 500 grams icing sugar or powdered sugar, sifted; 2 tablespoons full fat Greek yogurt or sour cream; 1-2 tablespoons full fat or whole milk, at room temperature; 1/8 teaspoon baking powder; 60 ml full fat or whole milk (for milk soak and finishing touches); 1/2 teaspoon vanilla extract

Jump to Recipe Print Recipe

The First Time I Made Milk Bar Birthday Cake

I remember the first time I tried to recreate Milk Bar Birthday Cake for a real celebration, not because I was being trendy, but because my niece asked for a cake that tasted like the box of sprinkles she loved. It began as curiosity and turned into a weekend project that filled the house with this warm, nostalgic smell of butter, vanilla and baking sugar. If you like dense, tender cake dotted with rainbow jimmies and a frosting that is almost pillowy, you will get why I keep making this one.

If you want to build something fancier later, I once used techniques from a stunning number cake tutorial to make themed decorations, but the heart of this recipe is very approachable and forgiving.

Gathering the ingredients, honestly

I never liked reading recipes that list everything in a dry column, so here’s what I pull out of the cupboard and fridge when I start. For the cake batter I use 230 grams (1 cup or 2 sticks) unsalted butter, softened, 200 grams (1 cup) caster sugar or granulated sugar, 2 teaspoons vanilla extract, and 3 large eggs at room temperature. The dry side is 315 grams (2 and 1/4 cups) plain flour or all-purpose flour, sifted, 3 teaspoons baking powder and a pinch of salt. For the wet additions I usually have 240 ml (1 cup) full fat or whole milk at room temperature and 60 ml (1/4 cup) full fat Greek yogurt or sour cream, room temperature. And of course, 50 grams (1/4 cup) funfetti sprinkles, rainbow jimmies, because this cake is a celebration.

Then there is the cookie crumb, that little crunchy surprise: 105 grams (3/4 cup) plain flour or all purpose flour, 50 grams (1/4 cup) caster sugar, 1 tablespoon cornflour or corn starch, 1 teaspoon vanilla extract, 60 grams (1/4 cup) butter, melted, and 3 tablespoons funfetti sprinkles. For the buttercream I call for 230 grams (1 cup or 2 sticks) butter, room temperature, roughly chopped, 2 teaspoons vanilla extract, 500 grams (4 cups) icing sugar or powdered sugar, sifted, 2 tablespoons full fat Greek yogurt or sour cream, 1-2 tablespoons full fat or whole milk, room temperature, 1/8 teaspoon baking powder, plus an extra 60 ml (1/4 cup) full fat or whole milk and 1/2 teaspoon vanilla extract for the milk soak and finishing touches. Seeing all that listed makes it feel like a party already.

Mixing, baking and the little touches that matter

I start by greasing and lining a quarter sheet pan, 9 by 13 inches, with baking or parchment paper. Preheat the oven to 180 C (350 F) standard, or 160 C (320 F) fan-forced. In a large mixing bowl I add the softened butter, sugar and 2 teaspoons vanilla and beat with an electric mixer on medium speed until the mixture is pale and creamy. Then I add the eggs, one at a time, beating after each addition so the batter stays smooth and doesn’t break.

In a separate bowl I whisk together the 315 grams plain flour, 3 teaspoons baking powder and a pinch of salt. I add half of this flour mix and all the milk and beat on low speed until combined. Then I add the remaining flour mix and the 60 ml Greek yogurt or sour cream and continue to mix on low until just combined and a thick, creamy cake batter forms. This is where I remind myself not to overmix, and gently fold in the 50 grams funfetti sprinkles by hand, so they stay colorful instead of bleeding.

Pour the batter into the prepared pan and smooth the top. Bake for approximately 25 to 30 minutes, until the cake is golden and a skewer inserted in the middle comes out clean. I set it on a wire rack to cool completely before the next steps.

While the cake cools I make the confetti crumbs. Preheat the oven again to 180 C (350 F) standard or 160 C (320 F) fan-forced. In a large mixing bowl I whisk 105 grams flour, 50 grams sugar and 1 tablespoon cornflour together. Pour in the melted 60 grams butter along with 1 teaspoon vanilla, stir briefly, then add 3 tablespoons sprinkles and stir until it forms wet crumbs that look like wet sand. Spread these out on a baking tray lined with baking paper and bake for 10 minutes, then leave to cool completely. They add the best texture contrast.

For the frosting place 230 grams butter in a large mixing bowl and beat on medium speed for 1 to 2 minutes until smooth and creamy. Add 2 teaspoons vanilla and 125 grams (1 cup) of the icing sugar and beat on low to combine, then turn up the speed for 30 seconds. Next I add 250 grams (2 cups) sugar along with 2 tablespoons Greek yogurt and beat on medium until combined. Scrape down the sides, add the final 125 grams (1 cup) sugar, the 1-2 tablespoons milk and 1/8 teaspoon baking powder, and beat on medium until the frosting is fluffy and creamy. The texture should be spreadable but not soupy.

A little personal tip here: if your buttercream looks grainy, keep beating for another minute. If it becomes too soft, chill it for 10 minutes and then whip again. I learned this the hard way at a picnic.

Assembly that feels fancy but is simple

Once the cake is fully cooled I gently remove it from the pan and peel off the parchment. I cut out three 6-inch layers using a 6-inch cake ring. You’ll get two whole layers and then two halves, which is perfect for building a tall, compact cake. I place a 6-inch cake ring on a cake board or plate and line the inside with a sheet of acetate. I start by placing the two half pieces at the bottom, pressing down firmly. If there are any gaps I use extra cake scraps to fill in the holes and press down very firmly to make one even layer.

I make a simple milk soak by combining 60 ml full fat milk with 1/2 teaspoon vanilla extract. Spoon 2 to 3 tablespoons of this milk soak over the first cake layer. Add a few tablespoons of the vanilla buttercream and spread into an even layer. Scatter over a handful of the cookie crumbs for crunch and add a few extra tablespoons of frosting on top, without fully covering the crumbs. Add the next cake layer and repeat, spooning the milk soak, frosting and crumbs. Add the final cake layer, press down firmly, cover with the remaining buttercream and scatter the remaining crumbs. Chill the assembled cake in the fridge for at least 1 hour to set.

A quick tip about the soak, it is subtle but essential. Don’t saturate the cake or it will get soggy, 2 to 3 tablespoons per layer is all you need.

A few favorite ways to serve, variations and keeping it for later

I usually serve this with a cold glass of milk or a cup of straight black coffee. If you want to get playful, serve alongside a scoop of vanilla ice cream or use cookie crumbs as a garnish on the plate. If you are planning a party, cut the cake and set the slices on small plates so everyone can admire the confetti inside.

For variations, try folding in chocolate chips with the sprinkles for a chocolate-sprinkle combo, or swap the Greek yogurt in the batter for sour cream for a tangier crumb. You can also make smaller cupcakes using this batter, adapted into chocolate and vanilla birthday cupcakes styling, or press the crumbs on top and pipe the buttercream for single-serve desserts inspired by birthday cake macarons techniques. If you want to make this ahead, assemble the cake and keep it in the fridge for up to 3 days, or freeze individual slices wrapped tightly for up to a month. When serving from frozen, let slices sit at room temperature for 30 minutes so the frosting softens.

One final memory: my nephew blew out the candles while a little crumb escaped and stuck to his cheek, and everyone laughed. That moment is why I love this recipe, it feels celebratory without being precious.

If you want another flavor inspiration, I sometimes layer components with a banoffee birthday cake approach, replacing crumbs with caramelized banana bits for a totally different mood.

Conclusion

If you want to compare my version with the original, Milk Bar’s own Birthday Cake Recipe | Milk Bar is a great place to see the inspiration and original techniques. For an approachable, step-by-step adaptation that inspired some of my shortcuts, there is a helpful easy homemade guide at Milk Bar Birthday Cake (Easy Homemade Version) – Sweetest Menu.