1Preheat the oven to 350F. Place your leftover turkey bits, veggies, stuffing, potatoes - whatever you have, but make sure it's at least half turkey - in the bowl of a food processor and add enough gravy and stock to process it into a mixture with the texture of thick, chunky pasta sauce or gravy. Blend in the egg, too.
2Pour the mixture into a bowl and add enough flour to make a workable dough. Roll it into balls and press down with the tines of a fork on a cookie sheet, or roll or pat out on a floured surface and cut into biscuit shapes. Place on a parchment-lined sheet and bake for 20 minutes, or until golden. To get them nice and hard, turn the oven off but leave them inside as the oven cools - when they're completely dried out, they'll last indefinitely. If they still have some moisture to them, keep them in a sealed container like you would any other cookie.
3Makes about 3 dozen treats, depending on their size.