Blend in blender on high speed 1/2 minute or until smooth. Pour this mixture into the top of a double boiler and add 1/4 c oil. Stir gently with a whisk over gently boiling water until it begins to thicken and egg is completely cooked. Chill several hours or overnight before using. If the dressing is too thick, add more Italian dressing as needed. Mix together equal amounts of fresh spinach, iceberg and romaine lettuce. Allow 2 C for each salad. Moisten leaves in dressing, do not saturate; let stand 5 minutes. Add onion rings, radish, etc.