Divide the mixture into approximately 2 heaping tablespoon portions and roll into balls using your hands. (Mixture should make about 12 meatballs).
Place meatballs on a foil-lined baking sheet and broil for about 5-6 minutes, remove the pan and flip meatballs over. Broil on the other side for an additional 5-6 minutes, or until golden brown on the outside but not cooked through.
While the meatballs are browning, heat marinara sauce in a large skillet over medium-high heat until it begins to bubble slightly. Season marinara sauce as needed.
Add meatballs, cover and reduce heat to low. Simmer for 1 hour, or until meatballs are cooked through and the internal temperature reaches 165 degrees. Remove the lid for the last 15-20 minutes of cooking time to allow the sauce to reduce and thicken a little.
Serve immediately or let cool and store in an airtight container in the refrigerator for 3-4 days or in the freezer for up to 4 months (thaw and reheat as needed).