Preheat oven to 375°.
Separate dough into triangles. Press triangles together to form a single round crust on a 12-inch pizza pan coated with cooking spray. Crimp edges of dough with fingers to form a rim.
Cook sausage in a large nonstick skillet over medium heat until browned, stirring to crumble. Drain.
Top prepared dough with sausage, potatoes, and cheese. Combine milk, salt, pepper, and egg substitute, stirring with a whisk. Carefully pour milk mixture over sausage mixture. Sprinkle with Parmesan. Bake at 375° for 25 minutes or until crust is browned.