Grease a casserole dish and cover bottom with lamb. Cover with a layer of sliced vegetables then a layer of potato. Repeat until all ingredients are used, finishing top with potato. Add seasoned stock, cover and cook 180C/370F for 1 1/4 hours. Remove lid, dot potato top with butter and continue to cook for 20 minutes to brown the potatoes.
Sprinkle with chopped parsley and serve.