Today isn't the only day we have leftovers. It's the only day when most people in America have the same sorts of leftovers. For many this is terrific and only requires some reheating. Leftovers can be planned overs. In fact I wrote an entire article on leftovers revised. If you absolutely can't stand having more of the same or you are trying to impress someone with your culinary savvy, there are plenty of creative ways to have a whole new gourmet experience with the pieces of yesterday.
Take the turkey. Yes, the whole leftover carcass will make a terrific soup. It's the backbone of fowl that creates a rich broth, so boil those bones with plenty of vegetables and herbs then strain it all an hour or so later and use that stock when sauteing onions, turnips, carrots, celery, greens, sea salt, and adding some of the meat back in towards the end.
If you are vegan, I'm sorry but Tempeh has no backbone. You could make a stew and crumble your leftovers into it.
Sweet potatoes can be mixed with a soft cheese or tofu, salt and pepper or your favorite spices to make a great raviloi filling. Buy some prepared wonton wrappers, fill with the mixture and just seal by moistening the edges of the wantons before pressing them together. Boil for a few minutes and just add to your stew or soup from above.
Bread dressing could become a main for breakfast or dinner, mix with egg and fry in a pan like a pancake or fritatta.
One woman I knew took leftover cranberry sauce and made dessert parfaits by placing layers of the sauce with chocolate syrup and ice-cream. You could easily do another version with whipped cream or tofu whip, alternating layers in a tall clear glass.
Let me know about your own creations.