Preheat your oven to 350°F (175°C) and prepare four 7-inch cake pans by greasing them and lining with parchment paper.

Make your vanilla layer cake batter, divide it into three equal parts, and color one with red food coloring and one with green.

Spoon the batters into each prepared pan in an alternating fashion, filling them to about two-thirds capacity.

Bake for approximately 35 minutes, until a toothpick inserted comes out clean. Allow cooling in the pans for 10 minutes, then transfer to the freezer for 45 minutes.

Trim any browned edges of the cooled layers and level the tops with a serrated knife.

Prepare the buttercream frosting by beating the softened butter until creamy, then gradually adding powdered sugar and heavy cream.

Stack the cooled cake layers starting with the uncolored layer, spreading a thin layer of buttercream between each layer. Apply a crumb coat and chill for 30 minutes.

Retrieve the cake, apply a thicker layer of buttercream frosting, and use piping bags to decorate with vertical stripes or swirls. Finish with festive sprinkles.