01 -
In a large bowl, combine ground beef, egg, milk, breadcrumbs, grated Parmesan, chopped onion, minced garlic, parsley or basil, salt, and pepper. Mix gently by hand until just incorporated. Avoid overmixing for tender meatballs.
02 -
With lightly oiled hands, form mixture into golf ball-sized meatballs, about 1.5 inches in diameter, and place them evenly spaced on a rimmed baking sheet lined with parchment or coated with cooking spray.
03 -
Preheat oven to 410°F (210°C). Bake meatballs on the center rack for 12 minutes, or until just cooked through. For deeper browning, broil on high for an additional 2 minutes at the end of baking.
04 -
While meatballs bake, heat olive oil in a deep skillet over medium heat. Sauté chopped onion for 2 minutes until translucent, add minced garlic and cook for 1 additional minute. Stir in crushed tomatoes, tomato paste, oregano, basil, red pepper flakes, salt, black pepper, and sugar or baking soda. Bring to a gentle simmer and cook uncovered for 10 minutes, stirring occasionally.
05 -
Transfer baked meatballs and any pan juices into the simmering marinara sauce. Gently stir to coat the meatballs, and let them simmer in the sauce for 2–3 minutes to absorb the flavors. Remove from heat for serving.