Description
This homemade rainbow cake uses one simple vanilla batter divided into colorful layers, stacked with classic buttercream frosting. It looks bold on the outside, but the process stays calm and approachable. Perfect for birthdays, school celebrations, or any day that needs something a little brighter.
Ingredients
For the Cake
2 ½ cups all-purpose flour
2 ½ teaspoons baking powder
½ teaspoon salt
¾ cup unsalted butter, softened
1 ¾ cups granulated sugar
4 large eggs, room temperature
1 tablespoon vanilla extract
1 cup whole milk, room temperature
Gel food coloring (red, orange, yellow, green, blue, purple)
For the Frosting
1 ½ cups unsalted butter, softened
4–5 cups powdered sugar
2 teaspoons vanilla extract
2–3 tablespoons heavy cream or milk
Pinch of salt
Instructions
Make the Cake Layers
Preheat oven to 350°F (175°C). Grease and line three 8-inch round cake pans.
In a bowl, whisk together flour, baking powder, and salt. Set aside.
In a large bowl, beat butter and sugar until light and fluffy.
Add eggs one at a time, mixing well after each addition. Stir in vanilla.
Add dry ingredients and milk alternately, mixing just until combined.
Divide batter evenly into separate bowls. Tint each bowl with gel food coloring.
Bake layers one at a time or in batches for 18–22 minutes, until the center springs back.
Cool completely before frosting.
Make the Frosting
Beat butter until smooth. Gradually add powdered sugar.
Mix in vanilla, salt, and cream until soft and spreadable.
Assemble the Cake
Level cooled cake layers if needed.
Stack layers with a thin layer of frosting between each.
Apply a light crumb coat and chill for 15 minutes.
Finish frosting the outside. Decorate simply if desired.
Notes
Use gel food coloring for brighter layers without thinning the batter.
Baking one layer at a time keeps the layers even and stress low.
Slightly muted colors still look beautiful once sliced.
- Prep Time: 35 minutes
- Cook Time: 25 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American