Start with the lamb. This dish was born from necessity: shepherds in the British Isles using what they had, stretching precious meat with vegetables from the root cellar, covering everything with potatoes to hold in the warmth. It is peasant food in the best sense. Honest, filling, and deeply satisfying.

The lamb matters most. Pasture-raised animals that have eaten grass and moved freely on the land taste different from those raised in confinement. The fat carries flavor. The meat has depth. When you brown good lamb in a hot pan, you will smell the difference before you taste it.

Root vegetables belong here: carrots, celery, onion, maybe a parsnip if you find a good one. They should be fresh and firm, not the tired specimens that have lingered too long in cold storage. Cut them small so they meld into the filling, each bite a balance of meat and vegetable.

The potatoes deserve attention too. Waxy varieties hold their shape but turn gummy when mashed. You want starchy potatoes, Yukon Gold or Russet, that will whip into clouds when treated with butter and cream. The crust should be golden and crisp at the edges, soft and yielding beneath. This is a dish that asks for second helpings.