This mouthwatering Meatball Sub Sandwich with Slow Cooker Meatballs is warm and cheesy. 3-meat meatballs are cooked perfectly in a slow cooker. Meatball subs are the perfect weeknight dinner.
Heat the olive oil in a non-stick pan and saute the onions until tender and golden brown.
Combine all of the of the meatball ingredients together, except 3 cups of sauce.
When you have an even consistency, form uniform sized balls that are about 2 inches.
Pour 2 cups of sauce into the bottom of the crock pot.
Set the meatballs into the sauce in a single layer if possible. If you need to double up that is fine, just try to place them in the center for even cooking.
Pour the remaining sauce on top of the meatballs and then put the lid on.
Cook on high for 4 hours, checking occasionally to make sure nothing is burning.
Preheat the oven to 350 degrees. Place the hoagie rolls in the oven for about 5 minutes until they are lightly toasted.
Fill the hoagie buns with 3-4 meatballs and a little sauce from the slow cooker.
Sprinkle each with 1/4 cup cheese and herbs. Broil for 2-3 minutes to melt the cheese.