This was actually for my nephew's birthday, which was the same day as the Super Bowl this year. It's a one-layer 12x18 sheet cake frosted with buttercream, with fondant for the yard lines. The goal posts were purchased in a Wilton kit (I made some from fondant but they didn't set in time). I carved the football smash cake from a one layer 6-inch round cake, and frosted it with buttercream, then used fondant for the laces.