Keto Meatballs

In a large bowl combine beef, garlic, mozzarella, Parmesan, parsley, egg, salt, and pepper. Form into 16 meatballs.  In a large skillet over medium heat, heat oil. Add meatballs and cook, turning occasionally, until golden on all sides, about 10 minutes. Remove from skillet and place on a paper towel-lined plate.  To the same skillet, add onion and cook until soft, 5 minutes. Add garlic and cook until fragrant, 1 minute more. Add tomatoes and oregano and season with salt and pepper.  Add meatballs back to skillet, cover and simmer until sauce has thickened, 15 minutes. Garnish with Parmesan before serving.