lamb cut to half walnut size Oil, salt, white pepper, cumin, onion (for 400 g lamb, use 4.5 g salt) Marinate for 1 – 1.5 h
Roast on high heat 200C/392F for 20 mins flip, spread some cumin, and then roast for another 3 mins (originally 5-10 mins after flipping, but it's a bit too much)
optional: could add cilantro and scallion to saute quickly after it's done