Preheat oven to 350. Bring a large kettle of water to a rolling boil. Add the pasta shells (with a pinch of salt). While the shells are cooking; brown the ground chuck in a large skillet along with the onions, green pepper, garlic salt, salt and pepper. When done, drain well. Add 2 cups of the Ragu, brown sugar, and mix well. Set aside. Drain the pasta shells, soaking them in cold water so they will be easy to handle. After they cool, spoon hamburger mixture into shells and place in a 9x13 pan sprayed with Pam, putting them closely together so the meat will stay packed in firmly. Then take the ricotta cheese by small spoonfuls and drop over the tops of the shells. Cover with remaining Ragu left in jar and top with 3 cups cheddar. Bake at 350 for 35 minutes or until cheese is bubbly. Let set for 15 minutes before serving.