Put 4 pieces of bread in the pan. Lay mozzarella on all pieces of bread. Cover with a lid to keep the heat in and melt the cheese.
Once the cheese is melted, lay the sliced tomatoes and fresh basil onto the cheese.
Sprinkle with salt and drizzle the balsamic glaze on top.
Cover the sandwiches with the remaining pieces of bread.
Turn and cook on the other side for a few minutes or until the bread is golden brown.
Notes
Balsamic drizzle can be found at Italian specialty stores or the Italian foods department in your grocery store. You can also make it yourself by cooking down balsamic vinegar to a thick syrup-like consistency.