01 -
Preheat the oven to 410°F. Lightly oil a baking sheet or line with parchment paper.
02 -
In a large bowl, combine lean ground beef, minced onion, egg, breadcrumbs, Italian seasoning, parsley, garlic, salt, black pepper, and balsamic vinegar if using. Mix until evenly incorporated, being careful not to overmix.
03 -
Using 2-3 teaspoons of mixture per meatball, roll into balls and place on the prepared baking sheet.
04 -
Bake in the preheated oven for 10-12 minutes, or until lightly browned. Meatballs do not need to be fully cooked at this stage.
05 -
Heat olive oil in a large, oven-safe skillet over medium heat. Add chopped onion and sauté for 5 minutes until softened.
06 -
Stir in tomato paste, Italian seasoning, and minced garlic. Cook for an additional 2 minutes until fragrant.
07 -
Pour in red wine (or broth/water) and scrape up any browned bits from the bottom of the skillet.
08 -
Add diced tomatoes, tomato sauce, and brown sugar if using. Simmer over medium-low heat for 5 minutes, stirring occasionally. Season with salt and black pepper to taste.
09 -
Place baked meatballs into the skillet with the sauce, ensuring they are evenly coated.
10 -
Cover the skillet with a lid for a thinner sauce, or leave uncovered for a thicker consistency. Bake at 375°F for 10-15 minutes, or until meatballs are cooked through and the sauce is bubbling.
11 -
Sprinkle with fresh parsley and grated Parmesan before serving. Pair with spaghetti, mashed potatoes, or crusty bread.