Comfort more than nutrition usually comes to mind when you think of a meat-and-potatoes meal. This recipe qualifies as both. It has all the comfort of classic shepherd’s pie, but works in extra veggies, olive oil instead of butter, and leaner beef. Nobody will be the wiser, since it remains so flavorful and satisfying.INGREDIENTSFor the potato-cauliflower topping:1 1/2 pounds russet potatoes, peeled and cut into 1-inch pieces1 teaspoon kosher salt, plus more for salting the cooking water8 ounces cauliflower florets (2 heaping cups)2 tablespoons extra-virgin olive oil1/2 cup low-fat milkFreshly ground black pepper1/2 cup shredded sharp or extra-sharp cheddar cheese…