I have made this many many times. It is a family favorite and also makes lots of leftovers.
1 pound ground beef
1/2 cup bread crumbs (I like plain then add my own herbs and spices. I like dried basil, oregano, garlic powder and a dash of onion powder.)
1/4 cup chopped parsley
2 eggs, lightly beaten
1/2 cup grated Parmesan cheese (the good stuff, not from a can)
In a bowl, mix the ground beef (or turkey), bread crumbs, what ever herbs and spices that you like, eggs, and cheese. Season with bit of kosher salt and fresh black pepper.
Put a jar of Newman's Own Marinara and a can of diced tomatoes in the bottom of your crock pot.
Then I use my medium cookie scoop to make the balls and put them on the sauce/diced tomato mixture. Pour another jar of Newman's Own Marinara and a can of diced tomatoes.
Cover and cook on high for 5 1/2 hours.
These come out nice and moist and go perfect with your favorite pasta. Also you can double the meatball recipe and use another jar of sauce and one more can (15 oz) of diced tomatoes.