1/3 cup fresh flat-leaf parsley
1/3 cup Gorgonzola dolce or other soft blue cheese
1/3 cup sour cream
1/3 cup mayonnaise
1/3 cup well-shaken buttermilk
1 tablespoon distilled white vinegar
3/4 teaspoon salt
1/4 teaspoon black pepper
1/4 cup finely chopped fresh chives
1/2 head romaine, thinly sliced crosswise (5 cups)
1 small head radicchio, quartered and thinly sliced lengthwise (3 cups)
1 small head frisée, torn into bite-size pieces (3 cups)
2 Belgian endives, trimmed and thinly sliced lengthwise
Blend parsley, cheese, sour cream, and mayonnaise in a food processor until smooth. Blend in buttermilk, vinegar, salt, and pepper. Transfer to a bowl and stir in chives.
Toss lettuces together in a large bowl, then toss with a generous 1/2 cup dressing.
Cooks’ note:
• Dressing keeps 5 days, covered and chilled. Stir before using.