In a large mixing bowl, combine the ground beef, breadcrumbs, grated Parmesan cheese, milk, chopped onion, minced garlic, egg, parsley, oregano, basil, salt, black pepper, and red pepper flakes (if using).
Mix the ingredients thoroughly but avoid overworking the meat, as it can make the meatballs dense.
3. Shape the Meatballs
Lightly grease a baking sheet or line it with parchment paper.
Begin shaping the meat mixture into meatballs, about 1 to 1.5 inches in diameter. Roll them gently between your palms to form smooth, round meatballs.
4. Bake the Meatballs
Place the formed meatballs on the prepared baking sheet, ensuring they’re evenly spaced and not touching.
Bake in the preheated oven for 20-25 minutes or until they are cooked through and browned on the outside.