Rainbow Cake

• 3 cups all purpose flour(375 g)
• 1 tablespoon baking powder
• 1 teaspoon kosher salt
• 3 sticks unsalted butter, softened
• 2 cups granulated sugar(400 g)
• 5 large eggs, room temperature
• 2 teaspoons vanilla extract
• 1 ½ cups milk(360 mL), room temperature
• red food coloring
• orange food coloring
• yellow food coloring
• green food coloring
• blue food coloring
• purple food coloring
• nonstick cooking spray, for greasing

Vanilla Simple Syrup

• ¼ cup granulated sugar(50 g)
• ¼ cup water(60 mL)
• 1 teaspoon vanilla extract

Cream Cheese Frosting

• 2 blocks cream cheese, softened
• 1 stick unsalted butter, softened
• 1 tablespoon vanilla extract
• 32 oz powdered sugar(905 g)
• milk, as needed

Assembly

• 2 cups assorted sprinkles(240 g)
• 1 cup nonpareil sprinkles(120 g)

Special Equipment

• 1 round cake pan, 6 in (15 cm)
• 1 cardboard cake round, 6 in (15 cm)