In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, minced garlic, egg, and parsley. Mix well until all ingredients are evenly incorporated.
Shape the mixture into 1.5-inch meatballs and place them on a baking sheet.
Heat a large skillet over medium heat and brown the meatballs on all sides, about 5 minutes.
Pour tomato sauce over the meatballs, reduce heat to low, cover, and simmer for 25 minutes until meatballs are cooked through.
Season with salt and pepper to taste. Serve hot with pasta or on a sub roll.
Notes
For extra flavor, add a pinch of red pepper flakes to the meat mixture. Meatballs can be made ahead and frozen before cooking.