Pull one sheet pan out and onto a cooling rack, load with sandwiches, top with the second baking sheet, return this to the oven, and in 10 to 15 minutes, the sandwiches will be perfectly melted and golden brown. It's a good idea to flip the sandwiches halfway through cooking to ensure even browning, and in the end, you've got eight to 10 sandwiches with only two pans to toss into the dishwasher.