A lovely emerald green, this soup is as light and refreshing as a garden salad. It makes a splashy start to any summer meal, especially dressed up with its peppery salsa.

Soup

4 cups torn butterhead lettuce leaves (see Tip)
2 cups stemmed and torn baby spinach
1 cup fresh flat-leaf parsley sprigs
1/3 cup coarsely chopped shallot
¾ cup plain yogurt
2 tablespoons fresh lemon juice
2 cups vegetable or chicken stock
Salt and freshly ground pepper to taste

Salsa

1 tablespoon extra-virgin olive oil
1 tablespoons red wine vinegar
½ teaspoon sugar
1/8 teaspoon dry mustard
Dash of salt and freshly ground pepper
¼ cup red radish in 1- by 1/8-inch matchstick strips
¼ cup seeded cucumber in 1- by 1/8-inch matchstick strips

Purée all the soup ingredients, except the salt and pepper, in a blender until smooth. Season to taste.

Refrigerate in a covered container until chilled, at least 3 hours, before serving. Taste and adjust the seasoning.

Meanwhile, to make the salsa, whisk together the olive oil, vinegar, sugar, mustard powder, salt, and pepper in a small bowl. Stir in the radish and cucumber strips. Refrigerate in a covered container.

Serve the soup shallow bowls with a mound of the salsa spooned atop each serving.

Advance preparation

Refrigerate this soup and the salsa for up to 2 days in separate covered containers.