For the filling:

900 gr lean lamb, sliced into bite-size chunks
225 gr turnips
225 gr carrots
1 med onion
1 t thyme leaves
2 cups beef stock
2 stalks celery
4 T butter
225 gr canned stewed tomatoes
2 cups beef stock
Salt and fresh ground pepper

For the potato topper:

Make the stew first. Melt the butter into a fry pan and add the lamb over fairly high heat. Brown the meat thoroughly. Drain remaining butter or fat from the lamb.

Put the browned lamb and the stock into a deep casserole. Mix in the tomatoes and season to taste with the salt and pepper. Bring the mix to a boil, then reduce heat and cook until the lamb is tender to the taste, 45 mins to 1 hour. Add the vegetables, peeled, sliced and diced. Peel the celery, as well, taking the stringy veins out of the back. Add the thyme and cold stock and heat boil gently until the vegetables start to soften.

In a separate pan place the potatoes in slightly salted water and bring to a rolling boil. Boil the potatoes until they are just tender, but don't let them go to the point where they're dissolving. Remove from heat and add butter, milk and salt to taste. Mash the potatoes.

With a soft spatula spread the mashed potatoes over the top of the stew, covering it completely, but not mixing the potatoes into the stew.

Place the casserole into the oven on high heat, 400+c for 20 mins or until potatoes are beginning to brown on top. Remove from oven and serve.