Melt the butter in a saucepan over medium heat. Reduce the heat so the butter is just barely bubbling.
Simmer 10 to 15 minutes, skimming off the foam with a slotted spoon as it appears (the foam forms as the water evaporates out of the butter). Cook until no more foam appears, the bubbling stops, and the milk solids have settled to the bottom of the pan and are golden.
Strain the clarified butter through a coffee filter or cheesecloth. Use immediately or store refrigerated in a sealed jar or container.