Chef puts a gourmet twist on Thanksgiving Day leftovers

While chef Marc Murphy looks forward to Thanksgiving every year, he may just have a bigger soft spot for what comes after: leftovers.

Mr. Murphy, chef and owner of the Landmarc and Ditch Plains restaurants in New York, makes annual sport of repurposing his turkey-day leftovers for a party the next day.

"It's nice to have everyone over that day," Mr. Murphy says. "People will regale us with stories of their crazy aunts and uncles, the kids aren't in school—everybody's relaxed."

While many regard Thanksgiving leftovers as merely warmed-up turkey and dressing, Mr. Murphy has far greater ambition.

The chef, who typically cooks Thanksgiving dinner in either his New York apartment or his Long Island home, often turns turkey, gravy and mashed potatoes into a shepherd's pie—topped with shaved Gruyère cheese for extra kick.

The raves he got about the dish when he first made it a few years ago sparked his passion for "transforming leftovers."

The key to fashioning a second life for leftovers, Mr. Murphy says, is recognizing that "the leftover doesn't have to have a starring role—it can play a supporting role in a dish and you're bringing in other elements from your pantry to make it shine."

He turns mashed potatoes into crispy croquettes. "You can combine potatoes with any kind of cheese, form them into croquettes, roll them in panko—it's really simple," says Mr. Murphy. He serves them with a dipping sauce made with turkey gravy jazzed up with whole-grain Dijon mustard.

Cranberry sauce can be transformed into dessert. Mr. Murphy fills a pie with the sauce and tops it with Italian meringue. A flavor-packed ingredient such as shaved truffled pecorino cheese can add oomph to mashed potatoes or a torta made with leftover Brussels sprouts.

Sometimes, Mr. Murphy goes for a total departure. He once steeped leftover corn bread in cream, added fresh corn, strained it and then turned the concoction into ice cream, which he served with a chocolate soufflé cake. He mashed up leftover pumpkin pie with bourbon and turned that into a sauce for the soufflé.

Before Mr. Murphy gets creative, however, he makes sure the leftovers are stored correctly. He advises against placing sealed-up, warm food in a refrigerator because of the risk of bacteria build-up. He says, "Sometimes I go into people's homes and I see them store food that's warm and I think, 'Are they trying to kill their family?' "

If you don't have time for a dish to cool down before putting it away, he says, store it uncovered in the fridge until it cools, then cover it.

With salads, Mr. Murphy has leftovers in mind even before the Thanksgiving Day meal: He serves greens with dressing on the side. "Everybody always says, 'We should have a salad at Thanksgiving' and then they never get to that salad," he says. "Once you dress that salad, if no one eats it, it's going to be garbage."

He says the undressed greens can always be turned into a turkey frisée salad for lunch the next day.

While it can be tempting to try to use every scrap of leftovers instead of wasting food, Mr. Murphy tries not to keep leftovers for more than three days. Besides, he notes, "by then, you've got to be sick of them."

That leads to the practical rationale for the leftovers party. It's a potluck affair, with guests bringing their own day-after dishes and food served family-style. This tradition ends up as entertaining as it is tasty.

"Everybody starts going, 'Oh, you should try my stuffing,' " Mr. Murphy says.”It does become a bit of a one-upsmanship."