four 6-inch round cake pans; a 2- to 3-inch biscuit cutter
For the cake: Preheat the oven to 350 degrees F. Grease four 6-inch round cake pans with cooking spray and line the bottoms with parchment.
In a large bowl, whisk together the granulated sugar, flour, cocoa, cinnamon, baking powder, baking soda, salt and cayenne. In a medium bowl, whisk together the milk, oil, vanilla and eggs. Whisk the wet ingredients into the dry ingredients and then stir in the coffee.
Pour the batter into the cake pans and bake until a toothpick inserted into the center comes out clean. Begin checking for doneness at 23 minutes. Let cool in the pans for 10 minutes, then turn the cakes onto a cooling rack to cool completely.
For the frosting: Beat together the powdered sugar and butter in a large bowl until creamy. Add the heavy cream, vanilla, cinnamon and salt and beat to combine.
For the assembly: Once the cakes are cooled, use a biscuit cutter to cut out 2- to 3-inch circles from the centers of 2 of the layers. (Use these circles to make a mini cake or just eat them.) Place one of the uncut layers on a plate or cake board and spread on a layer of frosting. Stack up the 2 cut layers on top of that with a layer of frosting in between. Fill the hole to the top with the candy-coated sunflower seeds or your favorite candy. Frost the top of the cake, then top it with the remaining uncut cake layer and frost it all over.