I baked a birthday cake with sprinkles inside that hides a secret cascade of colorful confetti when you cut the first slice.

Jump to Recipe

I’ve been obsessed with getting a perfect ring of sprinkles around a cake, the kind that looks accidental but survives transport. In this Rainbow Sprinkle Cake tutorial I promise you’ll learn tricks I swear I only figured out after ruining a dozen pans.

I use unsalted butter in the batter and a splash of vanilla extract to wake up the flavor, and I’ll show you the step by step so the sprinkles actually stick to the sides instead of raining down. This isn’t just a pinata fantasy it’s a solid Birthday Cake With Sprinkles Inside kind of party trick you can pull off.

Ingredients

Print Recipe (No Advertisments)

Flour: backbone, gives structure and carbs, little fiber, makes cake tender.
Granulated sugar: sweetens boosts browning, nearly pure carbs, no real nutrients.
Butter: gives richness, fat adds moist crumb and flavor, helps frosting set.
Eggs: binders add protein, helps lift and color, stabilize the batter.
Milk: adds moisture some protein and fat, keeps crumb tender.
Vanilla extract: a little adds depth and aroma, it lift sweet flavors.
Powdered sugar: for frosting, ultra fine makes smooth buttercream, mostly carbs.
Rainbow sprinkles: adds crunch and color, mostly sugar, purely decorative treat.

Ingredient Quantities

2 1/2 cups (312 g) all purpose flour

2 1/2 tsp baking powder

1/2 tsp fine salt

1 3/4 cups (350 g) granulated sugar

1 cup (226 g) unsalted butter, room temp

4 large eggs, room temp

1 cup (240 ml) whole milk, room temp

2 tsp vanilla extract

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

6 cups (720 g) powdered sugar, sifted

2 tsp vanilla extract for frosting

3 to 5 tbsp heavy cream or milk, more if needed

Pinch of salt for the frosting

2 to 3 cups (300-450 g) rainbow sprinkles, mix of nonpareils and jimmies works best

Gel food coloring set (red, orange, yellow, green, blue, purple) or your preferred colors

How to Make this

Print Recipe (No Advertisments)

1. Preheat oven to 350 F and grease and line two 8 or 9 inch round pans with parchment, flour lightly or spray with baking spray; measure flour by spooning into the cup and level it so you dont end up with a dry cake.

2. Whisk together 2 1/2 cups (312 g) all purpose flour, 2 1/2 tsp baking powder and 1/2 tsp fine salt in a bowl and set aside.

3. In a mixer beat 1 cup (226 g) unsalted butter (room temp) with 1 3/4 cups (350 g) granulated sugar until light and fluffy, about 3 minutes; add 4 large eggs one at a time mixing well after each, then stir in 2 tsp vanilla.

4. Add the dry ingredients in three additions alternating with 1 cup (240 ml) whole milk (room temp) starting and ending with the dry mix, mix just until combined and scrape the bowl so no streaks remain, dont overmix or the cake will be dense.

5. Divide batter evenly between pans, smooth tops, bake at 350 F for about 22 to 30 minutes depending on pan size until a toothpick comes out with a few moist crumbs, cool 10 minutes in pans then invert to a rack to cool completely.

6. For the frosting beat 1 1/2 cups (340 g) softened unsalted butter until creamy, then gradually add 6 cups (720 g) sifted powdered sugar, 2 tsp vanilla, a pinch of salt and 3 to 5 tbsp heavy cream or milk until you get a spreadable consistency; add more cream if it feels too stiff.

7. If you want rainbow frosting, divide frosting into 6 small bowls and tint each with gel food coloring (red orange yellow green blue purple) since gel gives bright color without thinning, reserve about 1 to 1 1/2 cups plain for crumb coat.

8. Level the cake layers, place one layer on a turntable or serving plate, spread a thin even layer of frosting, stack the next layer, then apply a thin crumb coat all over and chill 20 to 30 minutes until slightly firm.

9. Apply a final smooth coat of frosting using an offset spatula and bench scraper while rotating; to attach sprinkles press 2 to 3 cups (300 to 450 g) rainbow sprinkles (mix of nonpareils and jimmies) into the sides by hand in small handfuls or use a wide measuring cup to tamp them gently for even coverage, work in sections and let excess fall onto parchment so you can reuse it.

10. Finish the top with extra sprinkles or piped colored rosettes, chill briefly so sprinkles set, store cake covered in the fridge up to 3 days or at cool room temp for one day, and bring to room temp before serving for best flavor.

Equipment Needed

1. Oven (preheat to 350 F)

2. Two 8 or 9 inch round cake pans lined with parchment paper

3. Stand mixer or electric hand mixer (with paddle or beaters)

4. Mixing bowls (one large, one medium) and a whisk

5. Measuring cups, measuring spoons and a kitchen scale for grams

6. Rubber spatula for scraping and an offset spatula for spreading

7. Wire cooling rack

8. Cake turntable and bench scraper for smoothing frosting

9. Several small bowls and spoons for tinting frosting plus gel food coloring

FAQ

Can I make the cake ahead of time? Yes. You can bake the layers a day ahead, cool them completely, wrap tight in plastic wrap and keep at room temp or refrigerate. For longer storage freeze layers up to 2 months, thaw in the fridge overnight then bring to room temp before frosting. The buttercream keeps in an airtight container in the fridge about a week, or frozen up to 3 months. When using chilled or frozen frosting let it warm a bit then whip it again, add a splash of cream if it seems too stiff.

How do I get bright, even rainbow colors without ruining the batter? Use gel food coloring, not liquid, so you get strong shades without thinning the batter. Add color little by little with a toothpick, stir until uniform. If you need pastel shades, add a bit of white frosting or use less gel. Also, don’t overmix after adding color or you’ll develop gluten and make the cake dense.

How do I keep sprinkles from bleeding into the batter? Toss sprinkles with about a teaspoon of the flour from the recipe before folding them in, that helps stop color bleed and sinking. Fold them in gently at the very end so they don’t melt or streak the batter. Using a mix of nonpareils and jimmies gives the best texture and color retention.

My frosting is too soft or too stiff, what now? If it’s too soft, pop it in the fridge for 10 to 20 minutes then rewhip, or add a bit more sifted powdered sugar 1/4 cup at a time. If it’s too stiff add 1 tablespoon of heavy cream or milk at a time and beat until spreadable. A small pinch of salt will cut the sweetness and help flavor too.

Can I swap ingredients like milk, flour or eggs? Some swaps are fine. Whole milk gives best texture but you can use buttermilk for a tangier crumb, or a non dairy milk in equal parts. All purpose flour can be replaced with a 1 to 1 gluten free flour blend but results may vary. For egg substitutions use a commercial egg replacer or 1/4 cup applesauce per egg for a denser cake. Keep in mind swaps may change texture and bake time.

What pans, oven temp and bake time should I use? This batter works well in two 8 or 9 inch round pans, or one 9×13 pan. Preheat oven to 350 F (175 C). For two 8 or 9 inch rounds bake about 22 to 30 minutes, for a 9×13 check around 30 to 35 minutes. Start checking with a toothpick in the center, it should come out with a few moist crumbs not wet batter. Oven temps vary so trust the toothpick test.

Rainbow Sprinkle Cake Recipe Substitutions and Variations

All purpose flour: swap for cake flour to get a softer crumb. To make cake flour from AP, per cup remove 2 tablespoons flour and add 2 tablespoons cornstarch. For 2 1/2 cups remove 5 tablespoons flour and add 5 tablespoons cornstarch. Or use a 1 to 1 gluten free flour blend by weight for a gluten free cake
Whole milk: use 1 cup buttermilk for a tangier, more tender cake. If you use buttermilk add 1/2 teaspoon baking soda to help with lift. For a nondairy option, full fat oat or soy milk swapped 1 to 1 gives the best richness
Unsalted butter: if you only have salted butter use the same amount and reduce the batter salt by about 1/4 teaspoon. For the frosting you can replace up to half the butter with vegetable shortening or a stable vegan butter to keep it firmer in warm weather, use equal weight
Eggs: per large egg, use 1 tablespoon ground flaxseed mixed with 3 tablespoons water (flax egg) for binding, or 1/4 cup unsweetened applesauce for moisture. Both make the cake a bit denser and moister, but they work well

Pro Tips

1) Use a scale, not cups, when you can. Flour and sugar volumes change a lot with how you scoop them so weighing the batter gives way more consistent cakes every time.

2) Get ingredients really close to room temp. If you forgot, put eggs in warm (not hot) water for 5 to 10 min and cut butter into small cubes so it comes up faster, or microwave 3 to 4 seconds at a time until soft but not melted.

3) Dont overmix once you add the flour. Mix on low, stop as soon as streaks are gone and finish folding by hand if needed; overworking develops gluten and makes the cake tough.

4) For a smooth frosting and neat sprinkle finish chill the crumb coat until slightly firm, then use a warm, dry spatula to smooth the final layer (dip spatula in hot water, dry it well). Press sprinkles in small sections and catch the excess on parchment so you can reuse them, and if colors start bleeding, apply sprinkles just before serving.

Rainbow Sprinkle Cake Recipe

Recipe by Louise Nightin

0.0 from 0 votes

I baked a birthday cake with sprinkles inside that hides a secret cascade of colorful confetti when you cut the first slice.

Servings

servings

Calories

968

kcal

Equipment: 1. Oven (preheat to 350 F)