Prepare a charcoal or gas grill for medium heat. (Medium is 325 degrees to 375 degrees. You should be able to hold your hand 4 to 5 inches above the grates for 6 to 7 seconds.)

Thinly spread mayonnaise on one side of each piece of bread. When you're ready to grill, take the bread, cheese, salt and a spatula to the grill. Clean the grates with a grill brush. (No need to grease the grates.) 3. 4. Place the slices mayonnaise side down on the grill. Evenly sprinkle half the slices with about 3/4 cup cheese. Cover the grill and cook until the bread is golden and the cheese is nearly all melted, 4 to 6 minutes. 5. Check on the bread often, moving slices around the grill as needed to avoid burning.

Use the spatula or your hands to top the cheese halves with the other toasted slices. Transfer to plates, press down slightly and sprinkle with salt.