Heat the olive oil in a large skillet over medium heat. Add the onion and garlic and cook until onion is translucent. Remove from heat and cool.
In a large bowl, mix the onion/garlic mixture (including the oil) ground beef, ricotta, parsley, Parmesan/Romano, egg, breadcrumbs, salt and pepper. Mix until well combined.
Shape into meatballs about the size of a walnut.
If you're making tomato sauce, drop meatballs into simmering sauce and simmer for 1 hour.
If you're not serving with sauce, in the pan you cooked the onion, brown meatballs on all sides and cook until no pink remains in the center.