In a small, heavy saucepan, melt butter over medium-high heat. When boiling vigorously, reduce heat to medium-low and begin skimming off white foam, tipping pan as needed.
Simmer and skim until only clear, honey-colored liquid is left. Pour into a jar with a lid. Once cool, ghee solidifies and keeps, chilled, indefinitely.
Note: Nutritional analysis is per tbsp.