In a large skillet, crumble and cook the hot Italian sausage over medium-high heat for 3 minutes. Stir in diced onion and cook for 5 minutes, or until sausage has browned.
Stir in pasta sauce and pepperoni slices and simmer for 5 minutes. Remove from heat.
Cut the biscuit dough into quarters and stir into the meat mixture with the pizza cheese blend.
Transfer to a casserole dish coated with cooking spray. Sprinkle with mozzarella cheese and bake for 20 minutes or until cheese has browned.