Hollandaise 1 T White wine vinegar one egg yolk 4 oz unsalted butter, cut into smallish cubes To start take 1 Tbs white wine vinegar (or lemon juice, or even water if preferred), some salt and pepper, and boil together until the vinegar is reduced by 1/2. This makes it less sharp. Cool slightly, and add 2tsp cold water, and an egg yolk. Reduce the heat - you want to proceed over a gentle heat to prevent the egg cooking. The pan should be slightly warmer than is required for butter to mel