1-First Step: Preheat your oven to 350°F and grease six 8-inch round pans. Sift together 3 cups all-purpose flour, 1 tbsp baking powder, and 1/2 tsp salt. This mise en place keeps things smooth for your rainbow layer cake.

2-Second Step: In a large bowl, cream 1 cup softened unsalted butter with 2 cups granulated sugar until light and fluffy, about 3 minutes. Add 4 large eggs one at a time, then mix in 1 tbsp vanilla extract. Alternate adding the dry ingredients and 1.5 cups whole milk, starting and ending with dry. Beat until just combined to avoid tough layers.

3-Third Step: Divide batter evenly into six bowls, about 1 cup each. Tint with gel food coloring: 1/2 tsp red for first, mix for orange (red+yellow), yellow, green (yellow+blue), blue, purple (blue+red). Stir gently. For vegan adaptations, ensure plant-based gels. Pour into prepared pans.

4-Fourth Step: Bake at 350°F for 15-20 minutes each batch, rotating halfway. Test with a toothpick for doneness. Cool in pans 10 minutes, then transfer to racks. Full cooling takes 1 hour to prevent soggy stacking in your easy rainbow layer cake recipe.

5-Fifth Step: Beat 2 cups softened butter until creamy. Gradually add 8 cups powdered sugar, 1/4 cup milk, and 2 tsp vanilla. Whip until fluffy. For low-calorie, use half the sugar and light dairy. This yields enough for crumb coat and final layer.

6-Sixth Step: Level cooled layers with a serrated knife. On a turntable, start with purple layer, spread 1/2 cup frosting, add blue, and continue to red on top. Apply thin crumb coat, chill 20-30 minutes. For gluten-free stability, chill extra.

7-Seventh Step: Frost smoothly with offset spatula and bench scraper. Pipe rosettes or add sprinkles. Chill 30 minutes before slicing. This rainbow cake for parties serves 12-16, perfect for birthdays. Total time: 3 hours. Slice with a warm knife for clean rainbow reveals. Check out a visual guide at Preppy Kitchen’s rainbow cake recipe.