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Rainbow Birthday Cake: Easy Homemade Sprinkle Buttercream

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A vibrant, moist rainbow birthday cake with colorful layers and creamy sprinkle buttercream. This recipe uses simple pantry ingredients and gel food coloring for true, vivid colors without altering the batter consistency.

Ingredients

Scale
  • 3 cups (375g) All-Purpose Flour, sifted
  • 1 ½ cups (300g) Granulated Sugar
  • 1 tablespoon Baking Powder
  • 1 teaspoon Baking Soda
  • 1 teaspoon Salt
  • 1 cup (226g) Unsalted Butter, softened to room temperature
  • 4 large Eggs, room temperature
  • 2 teaspoons Vanilla Extract
  • 1 ½ cups (360ml) Buttermilk, room temperature
  • ½ cup (120g) Sour Cream, full fat
  • Gel Food Coloring (Red, Orange, Yellow, Green, Blue, Purple)
  • 2 cups (454g) Unsalted Butter, softened for frosting
  • 6–7 cups (750g) Confectioners’ Sugar, sifted
  • 3–4 tablespoons Heavy Cream
  • 1 tablespoon Vanilla Extract or vanilla bean paste
  • ½ teaspoon Salt
  • ½ cup Rainbow Sprinkles

Instructions

  1. Preheat oven to 350°F (175°C). Grease three 6-inch round cake pans (or two 8-inch pans) and line bottoms with parchment paper. Dust with flour.
  2. In a large bowl, whisk together flour, baking powder, baking soda, and salt.
  3. In a stand mixer, beat softened butter and granulated sugar on medium-high speed for 3-4 minutes until pale and fluffy. Scrape down sides.
  4. Add eggs one at a time, beating well after each addition. Mix in vanilla extract.
  5. Reduce mixer speed to low. Add dry ingredients in three parts, alternating with buttermilk and sour cream. Start and end with dry ingredients. Mix until just combined.
  6. Divide batter into six equal parts. Add gel food coloring to each part and mix until uniform. Refrigerate for 15 minutes.
  7. Pour batter into prepared pans. Bake for 20-25 minutes (for 6-inch pans) or 25-30 minutes (for 8-inch pans) until a toothpick comes out clean.
  8. Cool cakes in pans for 10 minutes, then turn out onto a wire rack to cool completely.
  9. For buttercream, beat softened butter until creamy. Gradually add sifted confectioners’ sugar, heavy cream, vanilla, and salt. Beat on high for 3-4 minutes until fluffy. Fold in sprinkles.
  10. Assemble cake by stacking layers with generous amounts of buttercream between each layer. Frost top and sides, smoothing with a bench scraper. Decorate with extra sprinkles.

Notes

Ensure all dairy and eggs are at room temperature to prevent the butter from seizing. Use gel food coloring instead of liquid to maintain batter consistency and achieve vibrant colors. Do not overmix the batter after adding flour to keep the cake tender. Cool cakes completely before frosting to prevent the buttercream from melting.

Nutrition

Keywords: rainbow cake, birthday cake, sprinkle buttercream, homemade cake, moist cake, gel food coloring, vanilla cake, party dessert

Find it online: https://twirltaste.com/rainbow-birthday-cake-easy-homemade-sprinkle-buttercream/