Preheat your oven to the temperature called for on the box mix. Additionally, prepare your 9x13 pan as stated on the box.
Prepare the cake batter, but replace the fat (i.e. vegetable oil) with the bacon fat.
Bake the cake as stated on the box. After it comes out of the oven, let it stand for about 10 minutes. Then poke holes in the cake with the bottom of a wooden spoon. Pour the fudge sauce evenly into all the holes.
Refrigerate the cake overnight. Before serving top with Cool Whip and bacon crumbles.