Cut Parmesan into cubes and peel 2 garlic cloves. Pick parsley leaves from the stems.
Add Parmesan, garlic, parsley, and half of the onion to mixing bowl and chop for 8 seconds / speed 6. Use spatula to scrape down the sides of the bowl.
Add ground beef, sausage, breadcrumbs, egg, 1 teaspoon salt, ½ teaspoon pepper, 1 teaspoon oregano and mix for 18 seconds / speed 4.
With lightly dampened hands, shape each portion into 6 balls and arrange in deep steaming trays. Wash and dry mixing bowl.
Drain the mozzarella and cut into 6 slices. Set aside.
Peel the remaining garlic clove. Add garlic, remaining onion and oil to mixing bowl. Chop for 6 seconds / speed 6. Scrape down sides of mixing bowl.
Remove the measuring cup, sauté for 4 minutes.
Add tomatoes, tomato paste, oregano, sugar, salt and pepper to mixing bowl.
Attach the steamer set to the mixing bowl and steam for 12 minutes.
Carefully lift the steamer lid and place a piece of mozzarella on top of each meatball, put the lid back, and cook for 5 minutes / 250°F|120°C / speed 1.
Carefully remove the steamer set and set aside. Place the lid on the mixing bowl and purée the sauce for 6 seconds / speed 6.
Serve the meatballs with the sauce. Enjoy your meal!
