FOR THE POTATO SALAD: Cook 10 pounds waxy new crop potatoes in salted boiling water to cover. Peel and dice. Spread in 3 serving pans, 9 by 15 inches. Sprinkle with 1 cup finely chopped onion. Cover evenly with Hot Salad Dressing. With wide spatula turn potatoes carefully in the dressing to coat completely. Let stand in a warm place, covered, for half an hour. At serving time, sprinkle with 1 cup chopped green pepper, 4 cups finely slivered celery, and 2 cups diced cucumber. Carefully toss to mix ingredients. Adjust seasoning, if necessary, with salt, pepper, and cayenne. Separately grate the yolks and whites of 12 hard cooked eggs and sprinkle on the salad in patterns through a paper doily, keeping the colors separate. Makes about 50 servings, 2/3 cup each.
FOR THE HOT SALAD DRESSING:
Put a 2 quart pan into a roasting pan with hot water in it. In the pan, mix together 1/2 cup flour, 1/4 cup sugar, 1 Tablespoon each dry mustard and salt, 1/2 teaspoon pepper, and a generous dash of cayenne. Gradually add 1 quart hot milk, stirring until smooth. Cook, stirring, until the sauce bubbles and thickens. Cook 10 minutes, stirring often. Beat 4 eggs lightly, warm them with a little hot sauce, and stir them into the pan. Cook for a minute or two. Remove the pan from the hot water and add 1 cup full strength distilled vinegar (not the mild seasoned type). Swirl in 1/4 cup butter. If the sauce seems too thick, add a few tablespoons of water to thin it as desired. Taste and adjust the seasoning with more salt and pepper to taste. Makes 1 1/2 quarts.