Preheat the oven to 400° F.
Invert a non-stick muffin tin. Lay 3 strips of bacon over each of 8 cups, overlapping slightly to cover the indentation. Place another inverted non-stick tin directly over the tin with the bacon to hold it in place. Transfer the tins to the oven and bake, upside down, until the bacon is set but still soft, about 10 minutes. Carefully remove the top tin and bake until the bacon is crisp and brown, about 5 minutes more. (You might want to put a sheet pan on the rack below the muffin tin to catch any dripping grease). Let the cups cool completely before removing them from the tin.