Ingredients

1/2 cup low-fat buttermilk

1 tablespoon crème fraîche or sour cream

Finely grated zest of 1 lemon (1 teaspoon), plus 3 tablespoons fresh juice

Kosher salt and freshly ground pepper

1/2 cup extra-virgin olive oil

4 heads butter lettuce, such as Boston or Bibb, outer leaves separated, hearts left whole

1 fennel bulb, halved lengthwise, cored, and very thinly sliced crosswise (1 cup), plus 2 tablespoons finely chopped fronds

2 tablespoons finely chopped fresh parsley leaves

2 teaspoons finely chopped fresh marjoram or oregano

Preparation

In a large bowl, whisk together buttermilk, crème fraîche, and lemon juice; generously season with salt and pepper. Slowly whisk in oil. Gently toss lettuce leaves and hearts and sliced fennel with dressing, then add half each of fennel fronds, parsley, and marjoram and toss again.

Arrange salad on a platter; sprinkle with lemon zest and remaining fennel fronds and herbs. Season to taste. Serve immediately.