Here, the classic French salad becomes an elegant dinner, with mustard-glazed salmon in place of tuna, roasted vegetables and jammy eggs served over a jumble of salad greens tossed with a red-wine vinaigrette. Roasting the vegetables, rather than serving some steamed and some raw as you would for a traditional Niçoise, gives this dish great texture and a delicious contrast of temperatures. The vegetables and salmon are roasted on a single sheet pan, making this an elevated take on the…