Dredge lamb in flour; coat well. Sauté lamb in drippings in a medium Dutch oven over medium heat until browned. Add water, salt, and pepper, stirring well; cover and cook over low heat 1 1/2 hours.
Add lima beans, onions, and carrots; cover and continue cooking over low heat 30 minutes or until vegetables are tender.
Remove from heat, and spoon meat mixture into a lightly greased 2-quart casserole. Spoon mashed potatoes around edges of casserole.
Place casserole 5 to 6 inches from heating element. Broil 5 minutes or until potatoes are crusty brown.
Note: Mashed potatoes may be piped with a pastry bag for a more decorative effect.