Arugula and Potato Soup

Preparation

1. Step 1

   Melt two tablespoons of the butter in a heavy saucepan over medium low heat. Add the onions, leeks, garlic and salt, tossing to coat. Cover and cook slowly, tossing occasionally, until the vegetables have softened, about 20 minutes.

2. Step 2

   Add the potatoes, broth, ginger and nutmeg, stirring to combine. Raise the heat and bring the mixture to a boil, skimming off all the froth from the surface. Simmer, partly covered, until the potatoes are tender, 30 to 40 minutes.

3. Step 3

   Remove half the solids with a slotted spoon and puree until smooth in a food processor or a blender. Return the puree to the soup and add the cream or milk. Bring to a boil, then thin the soup if desired with additional broth. (The soup can be prepared in advance to this point, then returned to a boil at serving time.)

4. Step 4

   Scatter the chopped arugula over the surface and cover the pan. Cook until the arugula has wilted, about two minutes. Stir, add salt and pepper to taste, making sure to season the soup carefully. Swirl in the remaining tablespoon of butter and serve immediately.