Preheat oven to 400 degrees F. Prepare a baking sheet with non-stick cooking spray and set aside.
To a mixing bowl add ground beef, finely diced onions, bread crumbs, garlic powder, egg, grated parmesan cheese, salt, Italian seasoning, and 2 tablespoons of marinara sauce. Mix together until well combined, but do not over mix.
Form balls and place it on prepared baking sheet. Bake for 15-20 minutes or until meatballs are cooked through. Cooking time can vary depending on the size your meatballs.
Heat remaining marinara sauce and add cooked meatballs to marinara when ready. Serve and enjoy.
Notes
How to reheat meatballs:Reheat meatballs easily on the stovetop, oven or microwave. If reheating frozen meatballs try to allow them to thaw 24 hours before.If reheating on the stovetop, put the meatballs into a pan with the extra sauce and reheat on low/medium.If reheating in the oven, place the meatballs on a baking sheet or dish sprayed with nonstick spray. Reheat on 350 for about 10 minutes to get them heated throughout.If using the microwave, you can reheat a couple thawed meatballs in about 2 minutes.