4 Ingredient Meatball Subs

0 Add the meatballs to a Crockpot and pour in a jar of marinara sauce. 
1 Cook on low of 2 hours until the meatballs are ready. 
2 When the meatballs are done, take the fresh bread, slice down the middle, and add in the meatballs and the mozzarella cheese.
3 Broil the subs for 30 seconds.