Here's how I make mine:
this will make about 12 cups of grinders using 3 lbs. of italian sausage so about 9 servings.
1-2 onions cut into large chunks
1 -2 green pepper cut into strips
1 28 oz. can tomatoe puree (or favorite marinara sauce)
3/4 cup chili sauce (found next to the cocktail sauce in the ketchup aisle)
3 lbs. hot or mild Italian sausage links
On serving day :
Optional: Cheese: Provolone or pepper jack slices or mozzarella shreds
In a large skillet, saute the onion and peppers in a small amount of oil over medium heat till tender. Add in the tomatoes or marinara sauce, and the chili sauce. Stir well and simmer until the mixture thickens. Set aside to cool.
Grill, saute in a pan, or oven bake the sausage links. Set aside the sausages to cool.
Put cooled sausage in a 1 gallon freezer bag or container. Pour cooled sauce over the sausage. Seal and label. Freeze the bag laying flat to save space.
Thaw bag in the refrigerator overnight. Spray your crockpot with non stick cooking spray or use a crockpot liner bag. Dump the sausages and sauce into the crockpot and cook on low till heated through 2-3 hours or on warm till heated through 5-6 hours.