04Meanwhile, make gravy. Tilt roasting pan and spoon off fat. Place pan on stove over low heat, sprinkle in flour and whisk up browned bits from pan. When flour is just golden, pour in stock and whisk well. Add ground coriander and simmer until thickened to taste. Season with salt and pepper. Carve lamb into thick slices so that each piece includes crust. Serve with roasted potatoes and coriander gravy.