Simplest Watercress Soup

This recipe is adapted (okay, copied) from the fantastic book Let's Eat Paris! by François-Régis Gaudry. He's no stranger to French cooking: a longtime fixture on the culinary scene here, he’s a journalist and restaurant critic. His radio and television shows are known nationwide.

In my family, we make this soup all winter long, and at least twice a month. It comes together quickly, and goes down even faster, especially when we add a generous dollop of crème fraiche – or a swirl of heavy cream, either is delicious – over the top. It really is the simplest of soups!

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Prep Time 25

Ingredients

2 tablespoons (30 g) unsalted butter
1 medium onion (225 g), finely sliced
4 cups (1 liter) vegetable or chicken stock, optional
14 ounces (400 g) Russet, Idaho, or other high-starch potatoes, peeled and placed in a bowl of water to wait
1 bunch of watercress (about 7 ounces or 200 g), stems cut off, leaving only 2 inches (5 cm) of leaves at the top and washed
2 teaspoons salt
white pepper to taste
a few pats of butter (count 1 per person), for serving
a few tablespoons of crème fraiche or heavy cream (count 1 per person), for serving

Instructions

Heat the butter in a medium soup pot over medium low heat. Add the onions and cook gently and without browning, covered, for 10 minutes, stirring occasionally.
Add 4 cups (1 liter) of water or stock and bring to a boil. Cut the potatoes into 1-inch (2.5 cm) cubes.
Carefully add to the boiling water the potatoes and the watercress.
Add salt, and simmer for 20 minutes, partially covered.
Remove from heat and purée the soup using an immersion blender (or cool and use a blender). If it seems too thick, add a bit of water and stir.
When ready to serve, heat the soup gently, serve in bowls, and add butter and cream. Or have these ingredients directly on the table so guests can help themselves.

Notes

serves 3-4 as a starter, 2-3 as a main course with bread