If you are making the meatballs, mix the ground beef, eggs, parmesan cheese, bread crumbs, onions and garlic together.
Use a scale to weight out 2 oz portions or whatever size you want them. Or you can use a cookie scoop too. Roll into balls. *Tip - Wet your hands with water while shaping them and the mixture won't stick to your hands.
In a skillet over medium heat, brown them on all sides. Do not worry about cooking them through, you just want some good color on them.
Transfer them to the crockpot.
Mix together the au jus, ranch, beef broth or water, and pepperoncini juice. Pour over the meatballs. Place a few of the peppers on top. If using butter, place small pieces of it all over the top as well. (I don't recommend using butter if making the meatballs homemade, as they will produce a lot of fat on their own. I do recommend using it for the store bought ones.)
Cook on high for 2-3 hours or on low for 3-4 hours. If using frozen meatballs, you can cut this time down somewhat.
When they are finished, remove the peppers and meatballs from the crockpot. Mix together the cornstarch and water and mix that into the juice left in the crockpot along with the heavy cream. Stir until a thick gravy forms.
Place the meatballs back in there and cover them with the gravy. Serve over mashed potatoes, rice or rolls and enjoy!