Chicken Parmentier.

A great way to use up left over roast chicken.
Peel, slice and boil potatoes in salted water.
Place a few tomatoes that have been cut at the base in a cross shape in boiling water for a minute then drain. When cool enough to handle peel and chop.
While the potatoes are cooking fry sliced shallots, diced carrot, celery and chopped garlic in butter until softened, then add a dash of white wine and cook for a minute before adding tomato puree,  chopped tomatoes and chicken stock. Cook down for ten minutes or so before adding black olives, halved, the left over chicken and a hand full of chopped parsley, season to taste then decant into pie dishes.
When the potatoes are cooked mash with butter and/or oil and milk and/or cream - season with salt and pepper and spread on top of the pie dishes.
Sprinkle with Gruyere cheese and bake in the oven.