Watercress & Leek Soup

This soup is built on a simple technique: sweating the leeks and watercress slowly in margarine with a lid on for a full 15 minutes before any liquid goes in. That low, covered heat draws out the moisture and concentrates the flavors without browning, which would dull the watercress’s bright, peppery bite.

Stock goes in after the vegetables have softened, and the whole thing simmers for just 10 minutes. That’s all the watercress needs. Longer cooking turns it bitter and muddy green instead of the vivid emerald you want.

A teaspoon of cornstarch dissolved in cold water thickens the soup just enough to give it body without making it heavy. After blending, the soup should be velvety smooth with a clean, green flavor that’s equal parts leek sweetness and watercress pepper.

Kitchen Tips

• Stir occasionally during the sweating step and keep the heat low. Browning the leeks changes the entire flavor profile from delicate to caramelized
• Wash the watercress thoroughly. It grows in wet beds and can carry grit
• Blend in batches if needed, and vent the blender lid slightly so steam can escape
• This soup also works well served chilled in summer, like a cold vichyssoise with a peppery kick

Variations

• Swap watercress for spinach for a milder, more approachable flavor
• Add a diced potato to the stock for a creamier, heartier version
• Finish with a swirl of cream or a dollop of creme fraiche for richness