Combine the endive, apples, blue cheese, onions, walnuts and tarragon in a medium mixing bowl. Add the Soy-Sherry Vinaigrette (use as much or as little as desired) and season with salt and pepper.
Puree the sherry vinegar, soy sauce, Dijon mustard, shallots and egg yolk in a blender. With the motor running, emulsify the oil into the mixture. Season with black pepper (the salt from the soy will be enough to season the vinaigrette).
Recipe courtesy of Geoffrey Zakarian