
Drain the cooked pasta and combine with the cheesy sauce.
Pour pasta with sauce into a 9 x 9 casserole dish. Top with marinara, pepperoni slices, and reserved fontina.
Place casserole in the oven and bake until the cheese is all melted and bubbly, 15-20 minutes. Enjoy!
May be baked in a greased 9 x 9 casserole dish instead of skillet if preferred.