Frisee's natural bitterness becomes mellow when you toss bite-sized pieces with crisp and sweet apples in a creamy-sweet dressing.
In a small bowl, whisk together sour cream or creme fraiche, champagne or white-wine vinegar, and honey. Season with salt and pepper.
In a large bowl, toss frisee and apple with enough dressing to coat. Season with salt and pepper and serve immediately.