Preheat your oven to 350°F (175°C) and prepare three round cake pans by greasing them with clarified butter and lining with parchment paper.

In a large bowl, prepare the cake mix according to the package instructions. Divide the batter evenly into the three cake pans and smooth the tops.

Bake for 25 to 35 minutes, or until a toothpick comes out clean. Cool in the pans for 10 minutes before transferring to wire racks.

Cream softened butter until fluffy, then gradually add powdered sugar. Pour in cream as needed to achieve a smooth frosting consistency.

Divide frosting into four bowls. Leave one portion dark green and dye the others with gel colorings until vibrant.

Assemble the cake by placing the first layer on a plate, piping rings of colored frosting on top, alternating colors for the second and third layers.

Cover the entire cake with the dark green frosting and smooth with an offset spatula.

Apply Halloween sprinkles generously on the cake's top and sides.

Pipe decorative dollops on top and chill the cake for about 30 minutes before serving.