Potatoes are the best food, and new potatoes are even better. Potato salad should be one of the first things coming out of the kitchen as soon as new potatoes are ready in spring. Mustard and dill are a classic pairing, and lentils take the place of eggs here for a lighter, toothsome meal. Roasting the potatoes and tossing them in the vinaigrette while still warm are what make this dish. Don’t let them cool first!