Preheat the oven to 425

Cook meat (seasoned with oregano, onion powder & crushed red pepper flakes to taste) in a large nonstick skillet over medium-high heat until browned, stirring until it crumbles. Add mushrooms and cook until mushrooms are browned a bit as well. Add tomato sauce and cook until heated.

While meat cooks, coat a 9x13 baking dish with cooking spray. Unroll pizza crust dough and press into bottom and halfway up the sides of baking dish. Sprinkle half the cheese over the bottom of the crust. Top with meat mixture.

Bake uncovered in the oven at 425 for 12 minutes. Remove and top with remaining cheese. Put casserole back in the oven for 5 additional minutes or until crust is browned and cheese is melted. Cool 5 minutes before serving.