In a large bowl, combine the ground lamb and veal, garlic, coriander, fennel and cumin seeds.
Season with salt and pepper and mix well.
Cover and refrigerate for 30 minutes.
Preheat the barbecue to medium-high heat.
Brush clean and oil the grill.
Shape the meat mixture into 4 patties.
Grill the patties for 4 to 5 minutes on each side or until desired doneness.
Toast the buns and spread with hummus.
Place a patty on the bottom half of each bun.
Top with a slice each of onion, cucumber and tomato and some lettuce.
Serve immediately.
Note:
To add an exotic touch to your dish, try the condiments you can find in Middle-Eastern grocery shops, such as zaalouk, a tasty mix of roasted red peppers, eggplant and chilli pepper.