1 can (8oz) tomato sauce
1/4 tsp dried basil
1/4 tsp crushed red pepper flakes
1/8 tsp garlic powder
1 lb bulk Italian sausage
1 medium onion, thinly sliced and separated into rings
8 slices mozzarella cheese
8 slices French bread
1/4 to 1/2 c butter, softened
in a saucepan, combine tomato sauce, basil, pepper flakes and garlic powder. Bring to a boil over medium heat. Reduce heat; simmer for 15 minutes.
Meanwhile, shape sausage into four thin oval patties. In a skillet over medium heat, cook patties until no longer pink; remove and keep warm. In the drippings, saute onion until tender.
Place a slice of cheese on four slices of bread; top each with a sausage patty, onion and remaining cheese. Top with remaining bread. Butter the outsides of sandwiches. Cook on a griddle or in a large skillet over medium heat until both sides are golden brown and cheese is melted. Serve with herbed tomato sauce for dipping.