Blend: Pulse together mayonnaise, sour cream, scallion, thyme, capers, anchovy fillets and lemon juice in a food processor until smooth and pale green. Season with salt and pepper. Keep in covered container in refrigerator until ready to serve.

Assemble: In 6 clear individual bowls, arrange lettuce leaves in circles, one circle for each color of lettuce you are using: Arrange red leaf lettuce in a complete circle around the bowl’s edge. Then layer the Boston leaves inside the red leaf lettuce and end with the Bibb leaves, the yellow cluster at the center. Drizzle salad dressing on top and serve.

Serving Option: This may also be made in one large bowl and served as a large salad. Simply use the same layout of lettuce leaves, but use all of the lettuce for each layer.