Cook, flipping shanks every 20 minutes, until very tender, 2 hours to 2 1/2 hours. Remove the lamb shanks from the Dutch oven, and set aside.

Preheat the oven to 250°. Remove the shanks from the brine and rinse well. Clean and dry the casserole. Melt the lard in the casserole over moderate heat until it reaches 250°.