In a medium bowl, combine cold cooked rice, grated Parmesan cheese, finely chopped roasted red peppers, lightly beaten egg, salt, and ground black pepper.

Using 1/3 cup of rice mixture, shape into a ball.

Gently insert a 1/2-inch cube of Mozzarella cheese into the center of each ball.

Re-shape the rice mixture around the cheese cube to completely cover it.

Coat the rice balls with Italian-style bread crumbs.

Heat olive oil in a deep fryer or large pot.

Carefully lower the breaded rice balls into the hot oil and fry until golden brown.

Remove the fried rice balls from the oil and drain on paper towels.

Serve hot with marinara sauce.