Directions:

1. Put the lamb in a large bowl with the onion, garlic, egg yolk, breadcrumbs, half the mint, the oregano and Worcestershire sauce.
2. Season and mix with your hands, until all the ingredients are well combined. Shape into six small burgers, cover and chill for 30 minutes.
3. Place on the barbecue or griddle and cook for 5-6 minutes each side, until cooked through. Mix the rest of the mint with the yogurt and season with salt and pepper.
4. Serve the burgers in buns with the minty yogurt, lettuce, tomatoes and red onion.