Parsnip Watercress Soup

Watercress soup may sound healthy, but the addition of cream makes it decidedly rich, French and fatty. So, what if you substitute parsnips for cream? Like cream, parsnips are sweet enough to tame the bitter bite of watercress. They lend enough starch to help thicken the soup. They are certainly not the same soup, but to me, equally good.

2 tablespoons unsalted butter
2 thin leeks, white and light green parts only, finely chopped
Kosher salt
8 ounces (about 2 medium) parsnips, peeled and thinly sliced
1 quart chicken stock or water
3 cups packed watercress
Freshly ground black pepper
Crème fraîche, for serving (optional).

 1. In a medium saucepan, melt the butter over medium heat. Add the leeks and a pinch of salt and sweat, covered, stirring occasionally, for 3 minutes.
2. Add the parsnips and a pinch of salt, and sauté for a few minutes more.
3. Pour in the stock or water, bring to a boil and simmer, uncovered, for 25 minutes. Add the watercress during the last 5 minutes of the simmering.
4. Using a blender, puree the mixture until smooth and uniform. Season to taste with salt and pepper. If you choose, serve with a dollop of crème fraîche. Serves 4. –Jill Santopietro for The Boston Globe.