Found this recipe on a British recipe site. They say to serve it with "potatoes, baked in their jackets".
1# left over cooked lamb, cut into cubes
3 T butter
2 medium-sized onions, thinly sliced
1tsp dried thyme
3 bay leaves
freshly ground black pepper
14 oz canned tomatoes
3-4 pieces of bread, torn into small pieces
1.5 c sharp cheddar cheese, grated
Preheat the oven to 350. Meanwhile, melt 1T butter in a large frying-pan over moderate heat. Add the onions and saute them until golden and soft.
Put the onions in the bottom of a casserole dish, place the lamb on top and sprinkle in the thyme. Put in the bay leaves and season with salt and freshly ground black pepper. Pour in the tomatoes with their juice.
Melt the remaining butter in a large frying-pan, add the breadcrumbs and stir until the breadcrumbs are nicely browned and have absorbed all the butter.
Mix the breadcrumbs with the grated cheese and spread evenly over the tomatoes. Bake for 40 minutes, or until the top is crusty and all the cheese melted. Serve the casserole immediately.