Preheat oven to 350 degrees F. Heat oil & garlic in a skillet. Toss in the fresh spinach and allow to cook for 2 minutes, transfer to a cutting board and chop into small pieces. Set aside to cool. Heat more oil and onions in skillet. Bring a large pot of salted water to a boil. Place the cabbage head into the boiling water. In a large mixing bowl, combine the turkey, cooled spinach and onion, Parmesan, mozzarella, Italian seasoning and ½ cup of the marinara.