How to Make It
In a large bowl, whisk vinegar and mustard with a pinch each of salt and pepper. While whisking, add oils in a slow, steady stream to emulsify.
Toss dressing with lettuce, radishes, scallion and dill. Top with avocado and serve.
Recipe adapted with permission from the publisher, Clarkson Potter, from Home Cooking With Jean-Georges by Jean-Georges Vongerichten and Genevieve Ko. Copyright 2011.