Lamb is finicky. It’s not like beef, which forgives you. Lamb holds a grudge. Overcook it by two minutes, and it turns into a dusty, gamey monster. Undercook it, and well... that’s not great either.
But here’s the weird thing: lamb fat is a flavor bomb. That white fat cap insulates the meat. It melts slowly. So a slightly undercooked lamb is often more delicious than a slightly overcooked one. Trust the fat.
Also, did you know the best lamb is from sheep that are less than a year old? Older sheep are called “mutton,” and mutton tastes like a barn smells. So buy young lamb. You want spring lamb, not a retired farm manager.