Chop onion and garlic in a chopper. Take big bowl and transfer chopped onion and garlic. Add 1 tablespoon of seasoning, egg, and rice to the bowl and mix together.
Add ground meat and mix well. Season with salt and pepper. Make balls from the mixture.
Put tomato sauce in slow cooker; add same amount of water. Add rosemary and 1 tablespoon of seasoning, salt, and pepper. Mix the sauce.
Add meatballs to the sauce so that they don’t touch each other. Cover meatballs with sauce. Cover with lid and set on high for 4 hours. Serve and enjoy!