Hollandaise Sauce

Bring a cup of water to a very low simmer in a small saucepan. Whisk egg yolks and lemon juice together in a metal bowl. Set the bowl over the saucepan (water shouldn’t touch), then whisk vigorously, slowly streaming in the melted butter, until the sauce has thickened. (Don’t let the sauce get too hot and scramble.) Whisk in cayenne and salt. If sauce gets too thick, whisk in a small bit of warm water.