Step 1: Preheat oven to 375 degrees F. Brown meat and boil water for shells. (If using pepper & onions, add to meat while cooking.) Drain fat from meat (completely) and add seasonings, tomatoes, mushrooms, and spaghetti sauce to meat. Let simmer on low heat for 10 min while shells are cooking.
Step2: Combine sauce mix with shells and 1/2 of the mozzarella. Mix well and top with remaining cheese.
Step 3: Bake for about 15-20 min till cheese is golden brown.