Preheat the oven to 350 degrees.

Place a parchment circle on the bottom of two 8 inch baking pans. Spray the pans and set aside.

Place one stick of butter in a skillet along with the brown sugar, cinnamon, cardamom, allspice, nutmeg, and cloves. Heat over medium heat and cook until butter is melted. Remove from the heat.

In a large bowl combine the remaining stick of butter and the sugar. Cream until smooth.

Add in the eggs and egg yolk and mix well. Stir in the vanilla.

Add the melted butter and spice mixture and mix until combined.

In a medium bowl combine the flour, baking soda, baking powder, and salt.

Add half the flour mixture to the butter mixture and mix well. Add the buttermilk and mix until combined. Add the remaining flour mixture and stir until well combined.

Divide the batter between the two prepared pans.

Bake for 30 minutes.

Remove from oven and allow to cool 5 minutes. Run a knife around the edges and remove cakes from pans. Cool completely on a wire rack.

To make the frosting beat the butter in a large bowl until smooth. Add in the powdered sugar a half cup at a time, stirring after each addition. Stir in the vanilla and milk and mix until smooth.

Place 1 cup of frosting on top of one of the cake layers and smooth it out. Top with the second layer. Reserve 1/2 cup of frosting. Use remaining frosting to frost the top and sides of the cake.

Divide the remaining frosting into 4 bowls. Dye the frosting bright pink, bright blue, bright green, and bright purple. Use the different colors to draw an outline of the sugar skull, then to draw the eyes, nose, and mouth. Use the sprinkles to fill in the eyes, nose, and teeth and to decorate the sugar skull.

Use skulls around the edges and bottom of the cake.