Step 1

Preheat oven to 400°F. In a 9 1/2- to 10-inch cast-iron or ovenproof skillet cook ground beef and onion over medium heat about 5 minutes or until the meat is browned and onion is tender, using a wooden spoon to break up meat as it cooks. Drain off fat. Set meat mixture aside. Wipe skillet out with a paper towel; set aside to cool slightly.

Step 2

On a lightly floured surface, divide pizza dough in half. Roll one dough portion to a 12-inch circle (if dough is hard to roll, let stand for 5 minutes and then roll out). Press dough circle into the bottom and up the sides of the skillet. Spread the 1/2 cup marinara sauce evenly over the dough. Top with meat mixture, mozzarella cheese, mushrooms, sweet peppers, oregano, and the 1/4 to 1/2 teaspoon crushed red pepper. Roll the remaining dough portion into an 11-inch circle. Place dough circle over filling. Pinch edges of bottom crust and top crust together to seal. Using the tip of a sharp knife, cut slits in the top crust.

Step 3

Bake about 25 minutes or until crust is golden brown and filling is bubbly. Let stand for 5 minutes before cutting. Cut into wedges to serve. Serve with additional warmed marinara sauce. If desired, garnish with parsley and/or additional crushed red pepper. If desired, serve with Parmesan cheese.