Cooked lettuce might sound unappealing, but when puréed, it gives the soup a wonderful, silky-smooth texture. It’s also a different way to experience a familiar taste: divorced from the expected crispness, lettuce takes on a surprising character, simultaneously earthy and light, and perfectly correct for spring.

This soup is simple, beautiful, equally delicious hot or cold, and a great way to use up head lettuce before it goes bad. I imagine it would be absolutely stunning made with a true red-leaf lettuce like Merlot.

Steps

1. Heat the olive oil in a heavy stockpot or Dutch oven over medium heat. Sauté the onion until lightly browned; you want to develop some good caramelized flavor here. In the last two minutes of cooking, add the chile flakes and dried marjoram (if using fresh marjoram, add at the very end, just before puréeing, as the heat will destroy its flavor). Add the potato, vegetable stock, and salt and pepper to taste.
2. Bring to a gentle boil, then reduce to a low simmer. Cook for 15 to 20 minutes, or until the potatoes are soft and can be pierced easily with the tip of a paring knife. Add the lemon juice and lettuce, stir to wilt, and remove from the heat.
3. When it’s cool enough to handle safely, purée the soup with an immersion blender, or work in batches and use a traditional pitcher blender. Taste for seasonings, then serve, garnished with chopped spring bunching onion tops or scallion tops and a bold dollop of crème fraîche.