Place all of the ingredients for the turkey meatballs into a large bowl. With clean hands, get in there and mix everything up until the mixture is cohesive. Wash your hands and set up a baking tray with parchment paper.
With clean and dry hands, scoop up about 2 TBSP worth of the meatball mixture, gently but firmly roll it into a ball, and place it on the parchment-lined baking tray. Do this until you're out of the meatball mixture.
Place the tray in the fridge for at least 30 minutes to help firm up the meatballs. This will prevent them from falling apart in the skillet. While the meatballs are idle in the fridge, you can start your marinara.
After 30 minutes have passed, heat 1-2 TBSP of olive oil in a large cast iron or non-stick skillet over moderate heat. Carefully place the meatballs into the skillet one at a time. Cook the meatballs for 3-4 minutes per side, or until golden brown. When flipping them over, be sure to be gentle with them; silicone tongs work really well. If they meatballs seem to be sticking to the pan, let them cook for a little bit longer until they release. Don't force them, or else they will fall apart.
Once each side of the meatballs is golden, but not quite cooked through, add about half of the marinara sauce to the skillet—or enough to coat the meatballs. Bring the heat to low, and let the meatballs simmer in the marinara sauce for 10-15 minutes, or until the meatballs reach an internal temperature of 165° F.
Once the meatballs are cooked, you can serve them with marinara over pasta, with bread, or enjoy them on their own. Use any of the extra marinara for your pasta if needed.