Preheat oven to 450°. Cook ground round and sausage in a large skillet over medium-high heat, stirring often, 8 to 10 minutes or until meat crumbles and is no longer pink. Drain beef mixture, reserving 1 tsp. drippings in skillet. Reduce heat to medium.
Sauté onion in hot drippings 2 minutes. Add garlic, and cook 1 minute or until tender. Add mushrooms, and sauté 8 to 10 minutes or until most of liquid has evaporated. Stir in beef mixture, pasta sauce, Italian seasoning, and salt. Bring to a light boil, and simmer 5 minutes.
Meanwhile, unroll dough on a lightly floured piece of parchment paper. Invert 1 (9-inch) round baking dish or pie plate onto center of dough. Cut dough around edge of baking dish, making a 9-inch circle. Remove excess dough around baking dish; cover and chill, reserving for another use, such as Cinnamon Nuggets. Remove baking dish.
Pour beef mixture into baking dish, and sprinkle with cheese. Immediately top with dough circle. Cut an "X" in top of dough for steam to escape. Place baking dish on an aluminum foil-lined baking sheet.
Bake at 450° for 16 to 20 minutes or until crust is golden brown. Let stand 10 minutes before serving.
Note: For testing purposes only, we used Pillsbury Classic Pizza Crust.
Piecrust-Topped Pizza Pot Pie: Substitute 1/2 (15-oz.) package refrigerated piecrusts for pizza dough. Proceed with recipe as directed, omitting Step (Place entire piecrust over filling in baking dish in Step 4; press crust onto edge of dish to secure. Edges of crust will hang over sides of dish. Tuck excess crust under sides of dish, if desired.)