Saute onions. Add olive oil to a large nonstick skillet over medium heat. Cook the grated onion in the oil for about 5 minutes until it just begins to brown and the liquid evaporates. Remove from heat and allow to cool.
In a large bowl, combine the ground beef, ground pork, garlic powder, salt, pepper, Parmesan cheese, ricotta, egg and cooked onions. Mix together until the ingredients are well combined.
Scoop the beef mixture into 1 ½” balls (about the size of a golf ball). It will make about 25 meatballs.
Place meatballs in a single layer in the air fryer basket and cook at 375 degrees for 10-12 minutes, until browned and cooked through. Repeat with remaining meatballs, working in batches as necessary.