Place unsalted butter in a light-colored skillet or saucepan
Set the pan over medium heat
Let the butter melt completely
Stir or swirl the pan occasionally
Continue cooking as the butter foams
Watch for the milk solids to turn golden brown
Remove from heat when the butter smells nutty and the solids are amber-brown
Immediately pour the brown butter into a heatproof bowl to stop cooking
Use right away or let it cool before storing