This cake is pure joy in every slice. The first time I made it, my son gasped and said, “It’s like a rainbow inside!” That moment made the extra few steps totally worth it. And honestly? It’s way easier than it looks especially with my shortcut version below. If I can do it in a small kitchen with a timer going off and a kid tugging at my leg, so can you! 

Rainbow Layer Cake Recipe

Ingredients For the Cake:

• 2 ½ cups all-purpose flour

• 2 ½ tsp baking powder

• ½ tsp salt

• 1 cup unsalted butter, softened

• 1 ¾ cups sugar

• 4 large eggs

• 1 tbsp vanilla extract

• 1 cup milk

• Gel food coloring: red, orange, yellow, green, blue, purple

Shortcut option: Use 2 white cake mixes and follow box instructions.

For the Frosting:

• 1 ½ cups unsalted butter, softened

• 5 cups powdered sugar

• 2–3 tbsp milk or cream

• 1 tbsp vanilla extract

• Pinch of salt

Step-by-Step Instructions:

1. Prep the Pans:

1. Preheat oven to 350°F (175°C).

2. Grease and line six 6-inch or 8-inch round cake pans.
   Tip: If you don’t have 6 pans, bake in batches.

2. Make the Batter:

1. In one bowl, whisk flour, baking powder, and salt.

2. In another large bowl, beat butter and sugar until light and fluffy.

3. Add eggs one at a time. Mix in vanilla.

4. Add dry ingredients and milk, alternating between the two, until just combined.

3. Color the Layers:

1. Divide batter evenly into six bowls.

2. Add a few drops of each gel food coloring to create red, orange, yellow, green, blue, and purple batter. Mix each until color is even.

4. Bake the Layers:

1. Pour each colored batter into separate pans.

2. Bake 15–18 minutes or until a toothpick comes out clean.

3. Let layers cool completely before stacking.

5. Make the Vanilla Frosting:

1. Beat butter until creamy (2–3 minutes).

2. Slowly mix in powdered sugar, then vanilla, milk, and a pinch of salt.

3. Beat until fluffy and smooth.

6. Build the Rainbow:

1. Place the purple layer on your cake plate. Add a thin layer of frosting.

2. Continue stacking: blue, green, yellow, orange, red — with frosting in between each layer.

3. Frost the entire outside of the cake with remaining vanilla frosting.

4. Smooth it out or make swoops with a spatula for texture.

Optional Decorations:

• Rainbow sprinkles

• Piped rosettes or swirls on top

• Mini marshmallows or white chocolate clouds

• Cake topper with "You Are Magic" or "Happy Birthday!"

Nutrition (Per Slice, Approximate):

Calories: 470
Protein: 3g
Carbs: 60g
Fat: 24g
Sugar: 50g
Fiber: 0.5g