Place the lamb in a bag with buttermilk and marinate in the fridge overnight.
Preheat the oven to 160°C.
Place the lamb, buttermilk, and 200ml of water in a casserole dish and season well.
Cook the lamb for 3.5 hours while basting periodically with the liquid.
Remove lamb from the oven and rest for 10 minutes under greased foil.
Dry-toast the buckwheat in a saucepan for 5 minutes until golden and fragrant.
Mix the buckwheat with torn mint, parsley, salt, lemon juice, and olive oil.
Combine the lemon zest, lemon juice, yoghurt, onion, sugar, and seasoning to make the sauce.
Flake the meat and serve over the salad with the yoghurt sauce drizzle.