On four slices of bread, layer one slice of mozzarella, two slices of tomato, 1 teaspoon Parmesan cheese, a dash of garlic salt and six slices pepperoni. Top with remaining mozzarella and bread. Spread outside of sandwiches with butter.
On a hot griddle, toast sandwiches for 3-4 minutes on each side or until golden brown. Serve with pizza sauce.