Think of this as a classic leek and potato soup—only so much better. Parsnips add a deep, sweet roasted flavor, pairing beautifully with the creamy potatoes and caramelized leeks. I love this soup when it’s smooth and velvety, garnished with—my new obsession—roasted tomato-flavored pearls, but I’ve also served it chunky and rustic with croutons for garnish. It all depends on what you’re serving next. For an elegant dinner, pureed until smooth is better, and for a casual mid-week supper, try going more rustic. Either way, roasting the vegetables first brings out their flavors to the nth degree. No need to add a lot of salt: You can taste and adjust the seasonings at the end. Serves 4 to 6 1 1/2 pounds parsnips (about 4 to 5), peeled and cut into 1/2-inch cubes or coins 1/2 pound Yukon gold potatoes, diced into 1/2-inch cubes 2 leeks, trimmed and sliced into …