Clarified Butter

Cut the butter into even chunks and place in a heavy-bottomed saucepan over the lowest steady heat. Let it melt slowly without stirring — you want it to come apart gently, not boil. As it melts, the butter separates into three layers: a thin white foam of whey proteins rising to the top, a thick clear-yellow layer of butterfat in the middle, and the heavier milk solids (casein and lactose) sinking to the bottom. Do not rush this with high heat or you will scorch the solids before the fat is clear.

Keep the butter at a bare simmer for 8 to 12 minutes. The water in the butter (about 15 to 18 percent of its weight) boils off, the bubbling quiets, and the foam on top thins. Skim away the white foam with a spoon as it accumulates so it doesn't fall back in. The middle layer turns from cloudy to brilliantly clear gold, and the milk solids on the bottom settle and slowly toast. For pure clarified butter, stop while the solids are pale; for a ghee-like depth, let them turn a light hazelnut brown and the kitchen fill with a nutty aroma.

Let the pot rest off the heat for a minute so the remaining solids settle. Line a fine-mesh sieve with a few layers of damp cheesecloth (or a coffee filter) set over a clean, dry, heatproof jar. Pour the butterfat through slowly, leaving the toasted sediment behind in the pot — tilt and stop pouring before the dregs slide in. The cloth catches the last fine particles and any skimmed foam. What lands in the jar is clear, golden clarified butter. Cool to room temperature, then cap; it keeps for weeks at room temperature and many months refrigerated, where it sets to a firm, pale, grainy solid.