How to Clarify Butter
You'll find some recipes call for what is known as clarified butter.
Pure and simple, clarified butter is golden, melted butterfat with none of the milk solids that would cause butter to brown and burn when cooked at high temperatures.
1. Melt butter in a saucepan over low heat until it's completely liquid. It will separate into three layers: a foamy surface, a golden yellow butterfat, and a milky residue on the bottom.
2. Skim the foam from the surface and discard it, then slowly pour the butterfat into another container, leaving the milky layer behind.
One stick of unsalted butter will typically lose about 1 tablespoon of volume during clarifying.
Clarified butter will keep, if kept covered and refrigerated, for several weeks.