Rainbow Marble Cake Recipe - Colorful and Decadent Celebration Cake - Recipes by Clare

Ingredients

• 3 cups all-purpose flour.
• 3 cups granulated sugar.
• 2 1/2 tsp baking powder.
• 1 tsp salt.
• 1 cup unsalted butter, room temperature (2 sticks).
• 2 tsp vanilla extract.
• 1 cup egg whites (about 7 egg whites).
• 1 1/2 cups buttermilk, room temperature.
• 1/8 cup vegetable oil.
• Gel food coloring in purple, blue, green, yellow, orange, red.
• 3 cups unsalted butter, room temperature (for frosting).
• 11 cups powdered sugar (for frosting).
• 1 tsp salt (for frosting).
• 1/3 cup heavy cream (or whipping cream for frosting).
• 1 1/2 Tbsp vanilla extract (for frosting).
• Gel food coloring in purple, blue, green, yellow, orange, red (for frosting).