I just made my own Milk Bar Birthday Cake and it’s three layers of soft funfetti, dreamy vanilla buttercream and crunchy cookie crumbs that actually deserve a party.

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I’m obsessed with this Milk Bar Birthday Cake. It’s loud and soft and weirdly adult, all soft vanilla and crunchy cookie crumbs.

I love that it’s a Vanilla Birthday Cake With Sprinkles but not cloying sugar trash. The buttercream sings, the crumbs crack like little tiny secrets, and those rainbow jimmies sprinkles make every slice feel like a tiny celebration.

But I’m not into fake bakery glamour. I want real unsalted butter and honest vanilla sandwich cookies in the crumbs.

Pure sugar joy, but smarter. Eat it straight, no apologies.

Worth the mess. Every single bite wants a party.

Ingredients

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Cake flour: light structure, makes cake tender and soft.
Baking powder: lifts the cake, keeps it airy.
Fine salt: balances sweetness, sharp little pop.
Butter (softened): rich flavor and creamy crumb.
Granulated sugar: sweetness and that classic cake texture.
Vegetable oil: keeps cake moist and stays tender.
Pure vanilla extract: warm, cozy aroma you’ll sniff.
Eggs plus yolks: protein, structure, and silkier cake.
Whole milk: adds richness and thins the batter.
Sour cream or yogurt: tang and extra moistness.
Rainbow jimmies: fun color and tiny sugary snap.
Butter for buttercream: ultra creamy, smooth frosting base.
Confectioners sugar: makes frosting sweet and spreadable.
Vanilla in buttercream: simple, comforting flavor boost.
Heavy cream: loosens frosting, makes it silky.
Pinch of salt: cuts sweetness, brings things together.
Crushed vanilla cookies: crunchy milk crumb texture, cookie nostalgia.
Melted butter for crumbs: helps crumbs clump and toast.
Granulated sugar for crumbs: adds crunch and little sparkle.
Extra sprinkles: playful finish, instant party vibes.
Nonstick spray or butter: helps pans release without stress.

Ingredient Quantities

For the cake:

3 cups cake flour, spooned and leveled

1 tablespoon baking powder

1 teaspoon fine salt

1 cup (225 g) unsalted butter, softened

2 cups (400 g) granulated sugar

1/2 cup (120 ml) vegetable oil

1 tablespoon pure vanilla extract

4 large eggs + 2 large egg yolks, room temperature

1 1/4 cups (300 ml) whole milk, room temperature

1/2 cup (120 g) sour cream or full fat yogurt

1/3 to 1/2 cup rainbow jimmies sprinkles (use oven‑stable ones if baking)

For the vanilla buttercream:

1 1/2 cups (340 g) unsalted butter, softened

5 cups (600 g) confectioners sugar, sifted

2 teaspoons pure vanilla extract

2 to 4 tablespoons heavy cream or whole milk, to thin

Pinch of fine salt

For the milk crumb crunch:

1 1/2 cups (150 g) crushed vanilla sandwich cookies or vanilla wafer crumbs

3 tablespoons unsalted butter, melted

2 tablespoons granulated sugar

A pinch of fine salt

Extras:

Additional sprinkles for decorating (about 1/2 cup)

Nonstick spray or extra butter for pans

How to Make this

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1. Preheat oven to 350°F (175°C). Grease three 8 or 9 inch round cake pans and line bottoms with parchment, then flour lightly or spray with nonstick spray.

2. Whisk together 3 cups cake flour, 1 tablespoon baking powder, and 1 teaspoon fine salt in a bowl; set aside.

3. In a large bowl beat 1 cup softened unsalted butter with 2 cups granulated sugar until light and fluffy, about 3 to 5 minutes. Add 1/2 cup vegetable oil and 1 tablespoon vanilla, mix until combined.

4. Add the eggs and 2 yolks one at a time, mixing briefly after each. Alternate adding the dry ingredients and 1 1/4 cups room temp whole milk plus 1/2 cup sour cream or yogurt, beginning and ending with the dry ingredients, mixing until just combined; do not overmix.

5. Gently fold in 1/3 to 1/2 cup rainbow jimmies (use oven stable sprinkles if baking) so they are evenly distributed but not smeared. Divide batter evenly among prepared pans and smooth tops.

6. Bake 20 to 25 minutes or until a toothpick inserted comes out clean. Cool in pans 10 minutes, then invert onto racks to cool completely before frosting.

7. Make the milk crumb crunch by mixing 1 1/2 cups crushed vanilla sandwich cookies or vanilla wafer crumbs with 3 tablespoons melted butter, 2 tablespoons granulated sugar and a pinch of salt; spread on a sheet and bake at 325°F for 8 to 10 minutes until slightly toasty, cool and break up into crumbs.

8. For the vanilla buttercream beat 1 1/2 cups softened unsalted butter until creamy, then gradually add 5 cups sifted confectioners sugar. Add 2 teaspoons vanilla, a pinch of salt and 2 to 4 tablespoons heavy cream or whole milk to reach spreadable consistency. Taste and adjust salt or cream as needed.

9. Assemble the cake by trimming cakes if needed. Place first layer on a plate, spread a layer of buttercream, sprinkle some of the milk crumb crunch, repeat with second layer, then top with third layer. Crumb coat the whole cake with a thin layer of buttercream, chill 15 to 30 minutes, then finish frosting smoothly.

10. Press remaining milk crumb crunch around the sides and extra sprinkles on top (about 1/2 cup) for decoration. Refrigerate to set for 30 minutes before serving; bring to room temperature 30 minutes before slicing. Enjoy.

Equipment Needed

1. Three 8 or 9 inch round cake pans, greased and parchment lined
2. Stand mixer or hand mixer with paddle or whisk attachment
3. Mixing bowls, one large and one medium (or a couple bowls)
4. Measuring cups and spoons plus a kitchen scale for accuracy
5. Rubber spatula and a large metal or silicone spoon for folding
6. Whisk for dry ingredients and smoothing batter
7. Cooling racks and a cake plate or cardboard rounds for assembly
8. Offset spatula and bench scraper or long knife for frosting smoothness

FAQ

Q: Can I make the cake ahead of time?

A: Yes. Bake the layers, wrap tightly in plastic wrap, and freeze for up to 2 months. Thaw in the fridge overnight before frosting. If you refrigerate instead, keep cake layers for 3 days max.

Q: My batter looks lumpy after adding eggs, is that okay?

A: A few small lumps are fine. Just mix until combined and smooth but don’t overbeat once the flour is in or the cake can get tough.

Q: How do I keep the sprinkles from bleeding color into the batter?

A: Use oven stable jimmies if you’re baking them in the cake. Also toss sprinkles with a teaspoon of flour before folding in to help them stay suspended and reduce color bleed.

Q: My buttercream is too soft, what now?

A: Chill the bowl for 10 to 20 minutes, then rewhip. If it’s too stiff after chilling, add 1 teaspoon of cream at a time until spreadable.

Q: How do I get the milk crumb crunch crunchy and not soggy?

A: Toast the crumbs in a 350 F oven for 5 to 7 minutes before mixing with melted butter. Let them cool completely so the butter doesn’t steam them and make them soft.

Q: Any tips for a clean, even layer cake?

A: Use a kitchen scale to portion batter so layers bake evenly. Let layers cool 10 to 15 minutes in the pan, then invert to cool fully on a rack. Chill layers slightly before trimming and frosting for cleaner edges.

Milk Bar Birthday Cake Recipe Substitutions and Variations

3 cups cake flour: Use 3 cups all purpose flour minus 6 tablespoons, then whisk in 6 tablespoons cornstarch. This softens the AP flour so it behaves like cake flour. Works great if you don’t have cake flour.
1/2 cup vegetable oil: Substitute with 1/2 cup neutral oil like canola or light olive oil, or use 1/2 cup melted coconut oil for a slight coconut note. If using melted butter, use 3/4 cup melted butter for similar richness.
1/2 cup sour cream or full fat yogurt: Plain Greek yogurt is the best swap, same amount. If you only have low fat yogurt, add a tablespoon of melted butter to make up for the lost fat.
1 1/4 cups whole milk: Buttermilk at the same amount gives a bit more tang and fluff. Or stir 1 tablespoon white vinegar or lemon juice into 1 1/4 cups milk and let sit 5 minutes to make a quick soured milk.

Pro Tips

1) Make everything room temp, really. Eggs, milk, sour cream and especially the butter should be warm to the touch so they mix smooth and you dont get a lumpy batter. Cold ingredients make the batter curdle and that kills your rise.

2) Measure flour by spooning into the cup and leveling it. If you scoop with the measuring cup you’ll pack too much flour and the cake will be dry. Use a kitchen scale if you can, weighs are more exact and saves a lot of guesswork.

3) Use oven‑stable sprinkles and fold them in gently, just enough to spread them around. Overmixing will melt or smear the colors and leave streaks. Also consider chilling the pans for 5 minutes after you flip the cakes to make trimming easier.

4) Don’t skip the chill between the crumb coat and final frost. A quick 15 to 30 minute chill firms the buttercream so your final finish is much cleaner, and the milk crumb crunch sticks better. If your buttercream seems too sweet, add a tiny pinch more salt, it makes flavors pop.

Milk Bar Birthday Cake Recipe

Recipe by Samantha Dalling

0.0 from 0 votes

I just made my own Milk Bar Birthday Cake and it's three layers of soft funfetti, dreamy vanilla buttercream and crunchy cookie crumbs that actually deserve a party.

Servings

servings

Calories

1095

kcal

Equipment: 1. Three 8 or 9 inch round cake pans, greased and parchment lined
2. Stand mixer or hand mixer with paddle or whisk attachment
3. Mixing bowls, one large and one medium (or a couple bowls)
4. Measuring cups and spoons plus a kitchen scale for accuracy
5. Rubber spatula and a large metal or silicone spoon for folding
6. Whisk for dry ingredients and smoothing batter
7. Cooling racks and a cake plate or cardboard rounds for assembly
8. Offset spatula and bench scraper or long knife for frosting smoothness

Ingredients

For the cake:
3 cups cake flour, spooned and leveled
1 tablespoon baking powder
1 teaspoon fine salt
1 cup (225 g) unsalted butter, softened
2 cups (400 g) granulated sugar
1/2 cup (120 ml) vegetable oil
1 tablespoon pure vanilla extract
4 large eggs + 2 large egg yolks, room temperature
1 1/4 cups (300 ml) whole milk, room temperature
1/2 cup (120 g) sour cream or full fat yogurt
1/3 to 1/2 cup rainbow jimmies sprinkles (use oven‑stable ones if baking)
For the vanilla buttercream:
1 1/2 cups (340 g) unsalted butter, softened
5 cups (600 g) confectioners sugar, sifted
2 teaspoons pure vanilla extract
2 to 4 tablespoons heavy cream or whole milk, to thin
Pinch of fine salt
For the milk crumb crunch:
1 1/2 cups (150 g) crushed vanilla sandwich cookies or vanilla wafer crumbs
3 tablespoons unsalted butter, melted
2 tablespoons granulated sugar
A pinch of fine salt
Extras:
Additional sprinkles for decorating (about 1/2 cup)
Nonstick spray or extra butter for pans

Directions

Preheat oven to 350°F (175°C). Grease three 8 or 9 inch round cake pans and line bottoms with parchment, then flour lightly or spray with nonstick spray.
Whisk together 3 cups cake flour, 1 tablespoon baking powder, and 1 teaspoon fine salt in a bowl; set aside.
In a large bowl beat 1 cup softened unsalted butter with 2 cups granulated sugar until light and fluffy, about 3 to 5 minutes. Add 1/2 cup vegetable oil and 1 tablespoon vanilla, mix until combined.
Add the eggs and 2 yolks one at a time, mixing briefly after each. Alternate adding the dry ingredients and 1 1/4 cups room temp whole milk plus 1/2 cup sour cream or yogurt, beginning and ending with the dry ingredients, mixing until just combined; do not overmix.
Gently fold in 1/3 to 1/2 cup rainbow jimmies (use oven stable sprinkles if baking) so they are evenly distributed but not smeared. Divide batter evenly among prepared pans and smooth tops.
Bake 20 to 25 minutes or until a toothpick inserted comes out clean. Cool in pans 10 minutes, then invert onto racks to cool completely before frosting.
Make the milk crumb crunch by mixing 1 1/2 cups crushed vanilla sandwich cookies or vanilla wafer crumbs with 3 tablespoons melted butter, 2 tablespoons granulated sugar and a pinch of salt; spread on a sheet and bake at 325°F for 8 to 10 minutes until slightly toasty, cool and break up into crumbs.
For the vanilla buttercream beat 1 1/2 cups softened unsalted butter until creamy, then gradually add 5 cups sifted confectioners sugar. Add 2 teaspoons vanilla, a pinch of salt and 2 to 4 tablespoons heavy cream or whole milk to reach spreadable consistency. Taste and adjust salt or cream as needed.
Assemble the cake by trimming cakes if needed. Place first layer on a plate, spread a layer of buttercream, sprinkle some of the milk crumb crunch, repeat with second layer, then top with third layer. Crumb coat the whole cake with a thin layer of buttercream, chill 15 to 30 minutes, then finish frosting smoothly.
Press remaining milk crumb crunch around the sides and extra sprinkles on top (about 1/2 cup) for decoration. Refrigerate to set for 30 minutes before serving; bring to room temperature 30 minutes before slicing. Enjoy.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.