If there's one thing we can count on during the holidays, it's leftovers. And if there's one thing leftovers are really good at doing (besides getting forgotten in the fridge), it's turning a meh salad into a magnificent meal. A chef's salad - with its brilliant balance of crisp, protein-packed, and satisfying - is our favorite way to use leftover ham, turkey, and chicken. Simultaneously! Whatever combination of ingredients you choose, this simple mustard vinaigrette will really compliment the rich flavors.