Heat the canola oil (about 4 cups) over medium heat in a large, heavy-bottomed pan. Use a thermometer to keep the temperature at 375 degrees Fahrenheit, or check frequently with an instant-read thermometer. If the oil is too hot, the dough will cook before the cheese can melt.

While the oil is heating, roll out the dough onto a large cutting board. Roll over it once or twice with a rolling pin to stretch it into an even rectangle and flatten the edges. Cut the dough into six 5-inch circles (trace a bowl or lid with a knife to make even cuts).

Spread a tablespoon of marinara sauce on each round of dough, leaving the edges free of sauce. Sprinkle two tablespoons of grated mozzarella onto half of the round. Top with pepperoni and a sprinkle of fresh basil. Fold the dough in half and press the edges firmly together to create a seal.

Using a slotted spoon, gently place one panzerotti into the hot oil. Cook until golden brown, about 1 minute on each side. Cook 1 or 2 at a time so they don't overcrowd the pan. When you remove each pizza from the oil, place it on a paper towel to absorb excess oil. Sprinkle the top with grated Parmesan and a pinch of Italian seasoning. Serve right away with marinara sauce for dipping.