Wipe two slices of lamb cut one and one-fourth inches thick from centre of leg. Put in hot frying-pan, and turn frequently until seared and browned on both sides. Brush over with melted butter, season with salt and pepper, and bake in casserole dish twenty minutes or until tender. Parboil three-fourths cup carrot, cut in strips, fifteen minutes; drain, and sauté in one tablespoon bacon fat to which has been added one tablespoon finely chopped onion. Add to lamb, with one cup potato balls, two cups thin Brown Sauce, three tablespoons Sherry wine, and pepper to taste. Cook until potatoes are soft, then add twelve small onions cooked until soft, then drained and sautéd in two tablespoons butter to which is added one tablespoon sugar. Onions need not be sautéd unless they are desired glazed. Serve from casserole dish.