In a heavy, medium saucepan over medium-high heat, melt the butter, stirring occasionally with a large metal spoon. As the butter starts to melt, skim off and discard any foam that rises to the surface. Cook until all the water in the butter boils off, and the fat stops sizzling and turns a deep golden yellow. The milk solids at the bottom of the saucepan will be reddish brown. The entire process should take 12 to 15 minutes. Remove the saucepan from the heat and carefully pour the liquid through the cheesecloth-lined strainer into the jar. Seal the jar and store the ghee in a cool, dark place for up to 3 months, or indefinitely in the refrigerator.