Preheat oven to 375F and line baking sheet with parchment paper.
In a large bowl, add turkey, egg, feta, and oats.
In a food processor, add dill, spinach, onion, garlic cloves, zest and juice of lemon, cumin, salt, and pepper. Pulse until blended together well but still has some texture.
Pour herb mixture over top of turkey and mix everything together - I use my hands to ensure well blend.
Roll into meatballs using ~3 tbsp of turkey mixture and place onto parchment lined sheet.
Bake for 16-18 minutes or until internal temp reaches 160F. Let cool slightly before serving.
While baking, whisk together all of the yogurt sauce ingredients. Use as a dipping sauce for meatballs.
Serve with rice, veggies, on a Greek salad, in a pita, or just as is!