Classic Italian Panini with Prosciutto and Fresh Mozzarella

Use this simple sandwich recipe as a template and customize it to your liking. Use focaccia or ciabatta in the form of depressions, or try, for example, various herbs and cheese.
Hollow out the top and bottom halves of the bread, leaving a 1/2-inch thick crust; leave the torn bread for another use. Spread 2 tablespoons of mayonnaise on the cut side of each bread half. Sprinkle the bottom half of the loaf with basil and 1/2 cup cheese. Top evenly with the prosciutto, tomato slices, and remaining 1/2 cup cheese. Cover with the top half of the loaf. Cut the stuffed roll crosswise into 4 equal pieces.Preheat a grill pan over medium-high heat. Brush the mold with cooking spray. Put the sandwiches in the pan. Place a cast-iron or other heavy skillet on top of the sandwiches; press lightly to flatten the sandwiches. Cook for 3 minutes on each side or until the bread is lightly browned (leave the sandwiches in a cast-iron skillet while they cook).