In a large mixing bowl, gently break apart the beef with a fork. Add the onion, breadcrumbs, parmesan, pecorino-romano, ketchup, parsley, basil, salt, Worcestershire sauce and garlic powder and stir gently to combine. Stir in the egg until just incorporated.
Using your hands, shape the meat into 1-inch balls, to make about 60 meatballs.
In a large nonstick skillet, heat 2 tablespoons olive oil over medium-high heat. Working in batches, add the meatballs and cook, turning, until lightly browned, about 10 minutes, adding more oil when necessary. Drain on paper towels.