Chocolate Potato Skull Cake

Ingredients:

For the cake:

1 large Idaho® russet potato (enough to yield 1 cup mashed potato)
2 cups all-purpose flour
1/2 cup unsweetened cocoa powder, sifted plus more for dusting pan
1 teaspoon baking soda
1 cup unsalted butter, at room temperature
2 cups granulated sugar
2 large eggs
1 cup buttermilk

For the frosting:

1 cup unsalted butter, at room temperature
2 teaspoons vanilla extract
Pinch of salt
4 cups confectioners sugar, sifted
3 to 4 tablespoons half-n-half
To decorate if using skull cake pan:
Eyeball gumballs
Crushed chocolate graham crackers

Directions: