Roll out pizza dough and use a heart shaped cookie cutter to cut the dough into hearts. If you don't have a heart shaped cookie cutter you can create a paper template and cut around it with a sharp knife.
Make sure you have 2 hearts for each calzone. Place dough hearts on a greased baking sheet and preheat the oven to 400 degrees F.
Spread about a tablespoon of sauce on each heart. Chop pepperoni into small squares and sprinkle over sauce. Top with mozzarella cheese.
Stretch second dough heart over each calzone. Use a fork to pinch the calzones closed around the edges.
Spread melted butter over the tops of each calzone using a pastry brush or spatula. Bake for 15 minutes or until golden brown on top. Serve with extra pizza sauce.