Brown Butter (Beurre Noisette)

Brown butter — beurre noisette, the French call it 'hazelnut butter' for the colour and aroma — is one of the most rewarding small techniques in cooking. Melt unsalted butter in a light-coloured pan over medium heat; as the water cooks off, the milk solids drop to the bottom and slowly toast, turning amber, then deep brown, releasing a nutty, almost cookie-like aroma. The window is short: another thirty seconds and you're at burnt butter, which is bitter rather than sweet. Pour it immediately off the heat into a cool bowl to stop the cooking. Use it on pasta, fish, brown-butter cakes, or to bloom warming spices like Aleppo chili.