01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine ground beef, breadcrumbs, Parmesan, egg, garlic, parsley, milk, salt, and pepper. Mix gently by hand until just combined—do not overmix.
03 - Shape mixture into 16 evenly sized meatballs and place them onto the prepared baking sheet.
04 - Bake for 15–18 minutes, until lightly browned and cooked through.
05 - While the meatballs bake, heat olive oil in a large skillet or saucepan over medium heat. Add onion and cook for 3–4 minutes until softened.
06 - Add garlic and cook for 1 minute until fragrant.
07 - Stir in crushed tomatoes, oregano, basil, sugar, salt, and pepper. Bring to a gentle simmer.
08 - Add baked meatballs to the sauce. Cover and simmer on low for 15–20 minutes, allowing flavors to meld.
09 - Serve hot, topped with fresh basil and extra Parmesan if desired.