Béarnaise, a classic sauce that's a variation of hollandaise and typically served over steak, can be difficult to make. With this cooking hack, however, you can make a pseudo-béarnaise sauce that is easier to whip up and stores in the fridge for longer.
The sauce traditionally is made in a special piece of equipment that heats the clarified butter, egg yolks and other ingredients gently, gradually raising the temperature and keeping the ingredients stable (so the butter and eggs don't separate). If you use mayonnaise instead, however, you don't have to worry about the egg and butter separating and can use just a regular saucepan.
As NPR explains, turmeric colours the sauce so it looks like the real thing, and the mayo substitute tastes like a real béarnaise as well -- just with less effort.