Mutton doesn't fit much our western traditional cooking esthetics where we want tasty but subtle. Lamb and mutton are for different types of recipes. As a french guy selling and importing high end food in South East Asia, I've tasted quite a wide array of lambs.

The best lamb is young, but not too young. I'm not a fan of milk-fed lamb where I feel there is quite no taste. The right balance is slaughtered at around 90 to 150 days old. Agneau de Sisteron is a gem. You don't need to be highly skilled to cook it. For cutlets, just pan sear until pink inside. For roast and leg, oven, basted with salt olive oil, some garlic cloves inserted inside the meat. It's truly magnificent.

The older the animal, the bolder the recipes it needs. The best lamb/mutton I've ever had was in Marocco, a slow roasted lamb in honey and almonds. So tender it was served from the bone with a spoon. You'll notice that mutton is always cooked in a way to counter balance the strong muttony flavour and sublime it with contrasts. Mutton curries are also delicious for the same reason.