Potato, Parsnip, and Celery Root Soup
This is a great basic recipe that will nourish your soul and body.
Feel free to use any combination of root veggies, including rutabagas, turnips, or different potatoes. The cream adds a nice richness and velvety texture, but you can get a similar effect without the cream if you use a rich, creamy potato like a yellow finn or German butterball. And when it’s available, spring green garlic is a great substitute for the regular garlic for an added burst of flavor.
1 tablespoon unsalted butter
1 tablespoon extra-virgin olive oil
2 large leeks, white and light green parts only, sliced
2 large Yukon gold or other waxy potatoes (about 1 pound), peeled and diced
2 large cloves garlic, chopped
1 teaspoon ground mustard
4 large sprigs thyme
1 bay leaf
1/4 cup dry white wine or dry vermouth
4 cups homemade vegetable broth (or low-sodium store-bought broth)
1 cup water
1/4 cup heavy cream (optional)
1 tablespoon freshly squeezed lemon juice, more as needed
In a soup pot or large Dutch oven, heat the butter and oil over medium-low heat. Add the leeks and 1/2 teaspoon salt and cook, stirring occasionally, until soft and translucent, 6 to 8 minutes. Add the potatoes, parsnips, celery root, and garlic, cover the pot, and stir occasionally until the veggies are heated through and softening a bit on the edges, about 10 minutes. Add the wine and cook until the liquid has completely evaporated, about 1 minute.
Add the broth and water, cover the pot partially, and increase the heat to medium-high. Bring just to a boil, then lower the heat to maintain a gentle simmer. Continue to cook, partially covered, until the vegetables are completely soft and have started to break down a bit, 45 minutes to 1 hour.
To finish the soup, remove and discard the thyme stems and bay leaf and, working in batches, carefully puree the soup in a blender (or use an immersion blender). If you prefer a thinner soup, add a little more water to adjust the thickness.
Stir in the cream and the lemon juice and taste. Adjust with more lemon juice or salt as needed and reheat as necessary.