1. Preheat oven to 370 degrees. Cut top of peppers and reserve. Clean out seeds, and set in baking dish.
2. In large skillet over medium heat, saute onion and garlic in olive oil 2 minutes. Add pork, hamburger, salt and pepper, and cook until beef and pork is browned, about 10-12 minutes. Remove from heat, and drain excess fat. Add and combine remaining ingredients except cheese.
3. Stuff peppers with filling, and put reserved pepper tops back in place. Cover dish with foil, and bake for one hour.
4. Remove foil and pepper tops, sprinkle with cheese, and bake uncovered until cheese is golden brown, about 4 minutes. Remove and serve