2 tablespoons extra-virgin olive oil
12 mini bell peppers (see Cook's Note)
1 pound raw, sweet Italian sausage (either in bulk or as links, see Cook's Note)
1/2 cup finely grated Parmesan cheese
1 large egg, beaten
Freshly ground black pepper
1 cup shredded mozzarella
Mini bell peppers can be found in packages of 12 to 20 peppers in the produce section of most grocery stores. If your market doesn't carry bulk raw Italian sausage meat, purchase uncooked Italian sausage links, snip a hole in the casing at one end, and squeeze out the sausage meat.