Divide dough into 6 equal portions. Form each piece into a tight ball and place on a floured baking sheet. Cover lightly with plastic wrap and let rise in a warm place for 1½ hours, or until dough has approximately doubled in size.

Meanwhile, prepare the filling by adding olive oil to a large skillet. Place skillet over medium heat. Once hot, add sliced peppers, onions and salt. Sauté, stirring occasionally, for 5-6 minutes, or until peppers have begun to soften.

Add Italian sausage and {optional} red pepper flakes. Cook, stirring often, for 8-10 minutes, or until sausage is fully cooked. Set mixture aside to cool.

Preheat oven to 500°F.

Working on a well-floured cutting board or counter top, roll/flatten 1 piece of dough into an 8” round circle. (Note: Keep the remaining dough covered while working. Use additional flour as needed to ensure dough does not stick.)

Place 1/6 of the filling into center of the dough. Sprinkle 1/6 of the grated cheese on top.

Using a small bowl, whisk together egg with 1 Tbsp of water. Lightly brush the edge of half of the dough with the egg mixture. Fold dough in half and crimp edges with a fork to seal. Place calzone on a lightly oiled baking sheet.

Repeat process using remaining dough, filling and cheese.

Cut 2-3 small vents into the top of each calzone to let steam escape.

Brush the tops of the calzones with the remaining egg wash.

Bake for 10-12 minutes, or until calzones are golden brown in color.