Preheat oven to 350⁰F (190⁰C).
Sauté onions in olive oil until lightly browned.
Add garlic and spinach. Cook until spinach is wilted.
Add remaining filling ingredients and set aside.
In a large bowl, mix ground turkey, breadcrumbs, egg, garlic, oregano, salt and pepper.
Divide meat mixture into eight balls and press each one flat, about 1/4” thick.
Add filling to the middle of each and form back into balls making sure all the filling is covered.
Place on a baking sheet and bake for 30 minutes.
Top each meatball with a tablespoon of tomato sauce, sprinkle of parsley and parmesan. Return to oven for another 10 minutes. Serve hot.