- Preheat oven to 400°F. In a large skillet over medium heat, break up sausage and cook until it is brown.
- Remove sausage from pan and set aside. Add bell peppers, onions, and garlic and cook, stirring often, until slightly soft, about 5 minutes.
- Add mushrooms and cook about 5 more minutes.
- Remove pan from heat and add sausage, pepperoni, pizza sauce, and mozzarella and stir until completely combined.
- Add filling to a pie dish and lay the pizza dough on top. Sprinkle some cheese and a few pieces of pepperoni on top.
- Cover with foil and bake for 30 minutes. Uncover and bake for an additional 10 minutes until crust is golden brown.
- Top with fresh parsley and serve.