A note of caution on using leftover ingredients: you may create something that is truly sublime and you won't be able to exactly reproduce it! I made Chicken a la King for dinner (I still have lots of leftovers) and had about a half cup of a mustard cream sauce left over from a pork tenderloin, which I added. It made the dish a little richer but it also gave it more depth and complexity. The original sauce was cream, Dijon mustard, dry white wine (probably vermouth because it's what would have been open) and of course, the fond in the pan from the pork). A hit for sure, but alas, one that might not be repeated.

(Tip: always keep a bottle of dry vermouth in your pantry. It's a great stand-in any time you have a recipe that calls for dry white wine. It's cheap, doesn't require refrigeration and you won't be the least tempted to drink it!)