Cook bacon on medium-high heat in a large, nonstick skillet and set on paper towels or napkins to drain. Pour off all but 1-2 tablespoons fat. Turn heat down to medium-low and add egg whites.
As egg whites cook, mix egg yolks with water in double boiler on medium to medium-high heat. Water should simmer, not boil. Stir constantly with a fork until yolks increase in size and thickness and turn a pale, opaque yellow. Remove from heat and slowly stir in melted butter. Then add lemon juice and salt and cayenne pepper to taste.
Place cooked egg whites on a plate, top with bacon, then cover with Hollandaise sauce. Serve with warm crusty bread for dipping in the sauce.
Serves 1 for a full meal or 2 for a light breakfast.
Notes: The amount of butter in this recipe is less than in standard recipes for Hollandaise sauce. This is the smallest amount that I have found still produces an acceptable sauce. If fat is not a concern, however, increase the amount to 1/3 or 1/2 cup.
Egg whites usually cook in the same amount of time as the sauce, but keep an eye on them and remove them to a separate plate if they finish cooking before the sauce is done.