Cut the butter into slices or cubes so it melts faster and evenly.
In a large, heavy frying pan (or saucepan), melt the butter over low heat.
When it’s fully melted bring it to a gentle boil. The butter will start to foam and after a few minutes, the foam will break apart into clusters and sink to the bottom of the pan. If you want to use the foam skim it off the surface with a spoon before it starts to break apart. It’s not necessary to skim it off because all the solid bits will get removed later.
It is done when the bubbling mostly stops because that means the water is boiled out of the butter.
Strain the liquid butter through a fine-mesh sieve covered with a few layers of cheesecloth into a glass jar or container. This way all the solid bits get filtered out.
This recipe can easily be doubled. Because the water evaporates 1 cup butter makes slightly less than 1 cup of clarified butter.