Ingredients

• 2 cups chicken or vegetable stock
• 2 tbsp extra-virgin olive oil
• 2 shallots, finely chopped
• 2 bunches watercress, chopped (including tender stems)
• fine sea salt
• freshly ground black pepper
• 2 medium russet potatoes, peeled, thinly sliced
• 2 tbsp unsalted butter
• 1/3 cup crème fraîche
• 2 tbsp finely chopped fresh chives

Instructions

1. Bring stock to a boil. Meanwhile, in a large saucepan, heat oil over medium heat. Add shallots and cook until soft, about 4 minutes. Add watercress and season with salt and pepper; stir to wilt. Add potatoes and hot stock, bring to a boil, and cook for 2 minutes. Reduce heat; simmer until potatoes are tender, about 8 minutes.
2. Purée soup in a blender until smooth. Stir in butter until melted and season to taste with salt and pepper.
3. Ladle soup into bowls and top each with a spoonful of crème fraîche and some chives. Serve immediately.