Milk Bar-Inspired Birthday Cake
This cake was inspired by Milk Bar’s famous birthday cake, which has become part of our birthday tradition. I wanted to make a homemade version using ingredients I usually keep in the kitchen while cutting back a little on the refined sugar without changing the cake texture too much.
I kept the fun parts I love — sprinkle cake, birthday cake crumb, cream cheese frosting, a light milk soak, and the tall layered look. One 13×9-inch sheet cake gives you two full 6-inch rounds plus enough remaining cake to build the third layer.
Recipe at a Glance
Total time includes cooling and chilling, so it will vary depending on whether you make the components ahead.
A Few Helpful Notes
The 13×9-inch pan matters here. From one sheet cake, you can cut two full 6-inch rounds and use the remaining cake pieces to build the third layer inside the cake ring.
Split up the work if you want. The birthday cake crumb and sheet cake can both be made ahead. I like making the frosting and milk soak closer to assembly time.
The monk fruit sweetener is optional. I used some Lakanto to cut back a little on refined sugar without trying to turn this into a “healthy cake.” If you prefer regular sugar, simply replace the Lakanto portions with the same amount of the corresponding regular sugar.
Any sprinkles will work. I used natural-color sprinkles, which blended into the cake more after baking. If you want a brighter, more classic birthday-cake look, regular rainbow sprinkles will hold their color better.
Three tools make the layered version much easier: a 13×9-inch baking pan, a 6-inch cake ring, and a 6-inch acetate cake collar. The acetate helps hold the scrap-built bottom layer and the tall cake neatly in place.
Use it lightly. You do not need to use all of the milk soak. I used less than half of mine. A light brushing between the layers is enough.
Ingredients
Birthday Cake Crumb
- 75 g cane sugar
- 60 g Lakanto Baking Sweetener
- 25 g light brown sugar
- 90 g all-purpose flour
- 1/2 teaspoon baking powder
- 1/2 teaspoon salt
- 20 g sprinkles
- 40 g neutral oil
- 1 tablespoon vanilla extract
Birthday Sheet Cake
- 55 g unsalted butter, softened (about 1/4 cup / 1/2 stick)
- 40 g neutral oil
- 170 g cane sugar
- 60 g Lakanto Baking Sweetener
- 30 g light brown sugar
- 3 large eggs
- 110 g buttermilk
- 2 teaspoons vanilla extract
- 210 g all-purpose flour
- 35 g cornstarch
- 1 1/2 teaspoons baking powder
- 1/2 teaspoon salt
- 1/8 teaspoon baking soda (optional)
- 50 g sprinkles, for the batter
- 20–25 g additional sprinkles, for the top
Vanilla Cream Cheese Frosting
- 115 g unsalted butter, softened (about 1/2 cup / 1 stick)
- 110 g full-fat cream cheese, softened (about 4 oz / 1/2 of an 8 oz block)
- 160 g powdered sugar
- 50 g Lakanto Powdered Sweetener
- 1 tablespoon milk
- 2 teaspoons vanilla extract
- pinch of salt
Milk Soak
- 1/4 cup whole milk
- 1 teaspoon vanilla extract
Make Ahead
The birthday cake crumb and sheet cake are the easiest parts to prepare ahead.
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B
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Before You Assemble
Once the sheet cake is completely cool, make the frosting and milk soak.
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Assembly Visual Guide
One sheet cake becomes a tall three-layer cake.
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F
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Instructions
1. Make the Birthday Cake Crumb
1. Preheat. Heat the oven to 300°F. Line a baking sheet with parchment paper.
2. Mix the crumb. Combine the cane sugar, Lakanto, brown sugar, flour, baking powder, salt, and sprinkles. Add the neutral oil and vanilla and mix until you have a combination of small crumbs and larger clusters.
3. Bake Spread the crumb over the prepared baking sheet and bake for about 15 minutes. Let it cool completely before using.
2. Make the Birthday Sheet Cake
4. Preheat and prepare the pan. Heat the oven to 350°F. Line a 13×9-inch baking pan with parchment paper.
5. Cream the butter and sugars. Beat the softened butter, cane sugar, Lakanto, and brown sugar together for about 2–3 minutes.
6. Add the eggs. Mix in the eggs until incorporated.
7. Mix the liquids separately. Stir together the buttermilk, neutral oil, and vanilla. Slowly mix this into the butter mixture. It may look slightly separated during this stage, and that is okay.
8. Add the dry ingredients. Whisk together the flour, cornstarch, baking powder, salt, and optional baking soda. Add them to the wet mixture and mix until combined. Fold in the 50 g sprinkles.
9. Fill the pan Spread the batter evenly into the prepared 13×9-inch pan. Sprinkle the remaining 20–25 g sprinkles over the top.
10. Bake Bake at 350°F for about 28–38 minutes, checking toward the earlier end of the range. The cake is ready when the center is set and a tester comes out clean or with a few moist crumbs.
11. Cool completely. Let the sheet cake cool completely before cutting the layers. Do not try to assemble the cake while the sheet cake is still warm.
3. Make the Frosting + Milk Soak
12. Make the frosting Beat the softened butter and cream cheese together until smooth. Add the vanilla and salt. Gradually mix in the powdered sugar and Lakanto powdered sweetener, then add the milk. Beat for about 2–3 minutes until smooth and spreadable.
13. Make the milk soak. Stir together the whole milk and vanilla. You probably will not need all of it.
4. Assemble the Cake
14. Cut two 6-inch rounds Use the 6-inch cake ring to cut two full rounds from the cooled sheet cake. Keep all of the remaining cake pieces for the third layer.
15. Build the bottom layer Set the cake ring on your cake board or serving plate and line the inside with acetate. Fit the remaining cake pieces into the bottom of the ring, gently pressing them together to make one even layer.
16. Add the milk soak Lightly brush the cake with the milk soak. You only need enough to moisten the surface — do not soak the cake heavily.
17. Add frosting and crumb Spread a layer of frosting over the cake, then scatter birthday cake crumb over the frosting.
18. Repeat. Add one full 6-inch cake round and repeat the milk soak, frosting, and crumb. Add the second full round on top and repeat again.
19. Finish the top. Spread the remaining frosting over the top of the cake and decorate with more birthday cake crumb.
20. Chill until set. Leave the cake inside the acetate until it is cold and firm enough to hold the layers neatly. Remove the cake ring and peel away the acetate before serving.
FINISHED RESULT
The Finished Birthday Cake
The finished cake has soft sprinkle-filled layers, creamy frosting, a light milk soak, and little pieces of birthday cake crumb tucked between the layers. It still feels like a real celebration cake, just made in a way that works better for how I bake at home.
The cake itself is soft rather than dense, and the three-layer build gives you that tall birthday-cake look from just one sheet cake.
Sunny Table note: I like that this version doesn’t have to be perfectly polished. The exposed layers and crumb make it feel fun and homemade, which is exactly what I wanted for a birthday cake.
Sunny Table Notes
- One 13×9-inch cake makes all three layers. Cut two full 6-inch rounds and use the remaining cake pieces to build the bottom layer inside the cake ring.
- Level the sheet cake if needed. If your sheet cake bakes thicker or slightly domed, trim the top before cutting the rounds. This helps the cake stack more evenly and keeps the finished cake from getting too tall.
- The crumb recipe makes a generous amount. You may have extra after decorating the cake.
- Use the milk soak lightly. I used less than half of the amount listed. I think it helped keep the layers moist without making them soggy.
- The Lakanto is optional. I only used it to cut back a little on refined sugar. If you prefer, replace the Lakanto Baking Sweetener with the same amount of cane sugar and replace the Lakanto Powdered Sweetener with the same amount of regular powdered sugar.
- The frosting ratio worked well for me. I was worried that adding Lakanto powdered sweetener would create a noticeable cooling taste, but I did not find the cooling effect strong at this amount.
- Natural-color sprinkles look softer after baking. Mine blended into the cake more than standard bright rainbow sprinkles. Use whichever look you prefer.
- Regular vanilla gives a warmer color. I used regular brown vanilla extract. Clear vanilla would give the cake and frosting a whiter, more classic birthday-cake appearance.
- Freezing is optional. I froze my assembled cake because I was making it ahead for a birthday. You do not need to freeze the cake if you are serving it sooner. Just chill it long enough for the layers to set before removing the acetate.
- This homemade version was inspired by Milk Bar’s birthday cake, but adjusted for the ingredients and baking style I use at home.
