To make the meatballs, preheat oven to 450 degrees F. Prepare baking dish with parchment paper
Combine egg, garlic, Panko, Parmesan, parsley, 1/2 teaspoon salt and 1/4 teaspoon pepper in a large bowl. Stir with a fork until well combined.
Add ground beef. Mix lightly but thoroughly. Using hands, shape into 1-1/2-inch balls. Place on parchment-lined baking dish
Bake meatballs for 10-12 minutes, until they are cooked through (160 degrees F on an instant read thermometer).
While meatballs are in the oven, place all sauce ingredients in the crock pot and stir to combine.
Add meatballs, stirring gently to coat. Cook, covered, on low 5-6 hours, until meatballs are cooked through.
Remove bay leaves. Serve with spaghetti.