Preheat the oven to 400℉ (200°C). Prep a baking sheet with parchment paper and spray with a cooking spray to prevent the meatballs from sticking. Then finely dice or grate your onion, mince the garlic, and chop the fresh basil.
Combine all the ingredients including turkey, oatmeal, parmesan, basil, garlic, onion, egg, olive oil, Italian seasoning, and salt and pepper in a large bowl.
Mix to combine using either your hands, a wooden spoon, or a spatula. I use my hands for this part. Make sure all the ingredients are well distributed.
Scoop about 2 tablespoon of the meat mixture at a time and form into balls on the prepared baking sheet. Continue until you have 20 meatballs.
Use your hands to shape the meatballs, wetting your hands with water to make them less sticky. Brush or spray the tops with olive oil (optional).
Bake in the oven for 25-30 minutes. The meatballs are done cooking when the internal temperature reaches 165℉ (75°C) with a meat thermometer. Cooking time will vary depending on the size of the meatballs and the oven.