Peel and finely dice the garlic and onion. Chop the olives and place in a bowl with the garlic and onion.
Wash the thyme, shake dry and add the leaves to the bowl of olives.
Add the minced meat and season with salt and pepper. Knead with the dough hook of a hand mixer and divide into 4 equal portions.
Cut the feta cheese into 4 pieces. Shape each portion of turkey into a flat circle.
Place the feta cheese in the centre, fold the meat around to enclose and shape into a ball, then flatten slightly.
Place the balls in a baking tray and brush with oil. Grill under a hot grill for 15 minutes, turning halfway through.