Instructions

• In a medium bowl, combine the ground beef, ¼ cup diced onion, 2 minced cloves garlic, the bread crumbs, milk, Worcestershire sauce, mustard, salt, and pepper. Mix well to combine and, using wet hands, form the mixture into 16 evenly sized balls (each about the size of a golf ball).
• Place a large oven-safe skillet over medium heat. Generously mist the skillet with cooking spray. When the skillet is hot, add the meatballs, being careful not to crowd them.
• Cook the meatballs until browned on all sides, 2-3 minutes per side for a total of 8-10 minutes, or until cooked through. Then remove the meatballs to a clean plate and cover to keep warm.
• To the same skillet over medium-high heat, add the 2 teaspoons of olive oil and swirl to coat.
• Add the onions and cook until tender, stirring occasionally, 7-8 minutes.
• Add the 2 cloves garlic and cook for 30 seconds or until fragrant, stirring constantly.
• In a glass measuring cup, whisk the cornstarch into the broth until it is dissolved, then pour the broth mixture into the skillet. Use a spatula or spoon to scrape up any browned bits on the bottom of the pan.
• Increase the heat to high and bring the gravy to a boil, stirring constantly. Once boiling, reduce the heat to medium and continue to cook until thickened, stirring constantly, 4-5 minutes.
• Return the meatballs to the onion gravy in the skillet and spoon the gravy over them.
• Remove the skillet from the heat and top with the shredded cheese. Allow it to rest, uncovered, for 5 minutes to allow the cheese to melt and the gravy to thicken more.
• If desired, garnish meatballs with chopped fresh parsley.
• Store leftovers in an airtight container in the fridge for up to 4 days or freeze for up to 3 months.