Mix together the ground turkey, garlic, yellow onion, egg, panko, parsley, salt, and pepper. Form mixture into 2 tablespoon-sized meatballs.
Cook the meatballs all the way through either in a skillet on the stovetop or on a sheet pan in the oven.
Skillet method - heat the avocado oil in a large skillet over medium heat. Once hot, add the meatballs and cook on 3-4 sides until browned and cooked through, tossing every 4 minutes.
Oven method - preheat the oven to 375°F, and bake the meatballs on a rimmed baking sheet for 15-20 minutes, until a meat thermometer inserted into the middle of the meatball registers 165°F.
Optional step - cook the noodles in a pot on the stove according to package directions.
Optional step - while the noodles are cooking, add the marinara sauce to the skillet with the cooked meatballs and toss, then bring to a low simmer for 5-10 minutes.
Serve over noodles with a garnish of parmesan cheese (optional), and enjoy!