Pour 1 jar of sauce into bottom of slow cooker crock. Top with meatballs.
Cover meatballs with second jar of sauce, 1 C mozzarella cheese, and 1/4 C parmesan. Stir to combine.
Place lid on slow cooker pot and cook on high for 3 – 4 hours.
For sandwiches, slice buns open (optional - toast lightly before serving) and spoon the meatballs & sauce mixture inside the buns (lining the bun with meatballs.
Sprinkle meatballs with cheese(s) of choice.
The heat from the meatballs will slightly melt the cheese in the sandwich. Or, you can place the subs in the microwave for 30 seconds to melt the cheese. You can also broil them in the oven for a few seconds.
Recipe courtesy of MomEndeavors.com. Please visit Mom Endeavors for recipe updates and additional tips!