Butter one side of each slice of bread, and lay butter-side down.
Top generously with pepperoni slices.
Then add a couple of thick slices of mozzarella cheese, and top with buttered bread .
Toast on panini grill or griddle, or in a frying pan (with a metal lid weighing down the sandwich). It took 4 minutes on my griddle, so maybe two minutes on each side in a frying pan on medium heat, or till your bread is golden, and your cheese is wonderfully melted.
You can serve with your favorite pasta sauce for dipping, or just eat it as is, it’s delicious either way!