Slow oven roasted lamb
i guess it would depend on the size of the leg. i start with room temp lamb studded with garlic under the fat, then smeared with mustard and lemon juice.
15 minutes at 500, then lower temp to 325 and go about 27-29 minutes per pound for pink (med) maybe around 140 internal temp or 25 minutes for reddish pink (med-rare) or about 135 internal temp. remove to plate cover and rest 10 - 15 minutes.
no problem to cook lower and slow if you're checking temp.
if you want well done, i'd say go with braised shanks. they lend themselves better to a more stew-like dish.