Cook onions and garlic in olive oil until soft. Set aside to cool slightly.
In a large bowl mix all the ingredients together - onion, garlic, lamb, mint, cumin and season with salt and pepper.
Divide mixture into 12 equal amounts and roll into balls.
Flatten each into a burger shape and then leave to rest in the fridge for at least 10 minutes.
Cook on grill for between 6 and 8 minutes each side ensuring they are thoroughly cooked through before serving.