While the soup comes out very creamy, it is actually vegan. By adding a small amount of potato to the base, the soup becomes perfectly lush, with a velvet-like softness post purée. You don’t need very much potato (in fact, too much will give you a gluey, gummy soup), but that small amount binds everything together into a soup that’s filling enough to serve as a satisfying meal on its own, perhaps with a salad or a piece of cheese and grilled bread.
Once you master the potato technique you can use this recipe with any combination of fall or root vegetables you fancy. While Italians make this soup all year long (one of my favorite versions involves summer vegetables—eggplant, zucchini, and tomatoes—all cooked with basil and a little potato and then puréed), but it works magnificently with fall and winter vegetables in particular. Within the recipe, there is flexibility: You could use pumpkin, parsnips, rutabaga, or Jerusalem artichokes instead of celery root and turnips.
4 to 6
extra-virgin olive oil, plus 2 tablespoons for drizzling
small onion, peeled and minced
clove garlic, chopped
leek, trimmed, cleaned, and finely sliced
Salt and pepper, for seasoning
medium-sized potato (any kind will do), peeled and diced
2 1/2 cups
celery root (about 2 1/2 pounds), peeled and diced (or swap in another root vegetable)
large turnip (about 1 1/2 pounds), peeled and diced (or swap in another root vegetable)
In a large heavy-bottomed pot, like a Dutch oven, heat the oil gently. Add onions, garlic, leeks, and a pinch of salt and sauté gently until the alliums are soft and translucent.
Add the diced potato and enough water to cover the potatoes, about 1/2 cup. Add another pinch of salt and simmer for about 10 minutes.
Now add the celery root and turnip and add just enough of the remaining water to cover the vegetables. Add a pinch of salt and simmer until all the vegetables are cooked through and tender.
Remove from the heat and purée: in a food processor, a blender, or with an immersion blender. Purée until really smooth and not chunky at all. Taste for seasoning.
Eat with a drizzle of olive oil and a sprinkle of herbs or any other garnishes you like: crispy pancetta or bacon lardons; finely diced shallot or chives; a dollop of sour cream, Greek yogurt, or crème fraîche in place of the olive oil; a little grated Parmigiana cheese or any hard aged grated cheese; a sprinkling of Aleppo or Urfa pepper.