Heat the unsalted butter in a heavy-duty saucepan over low-medium heat without a lid until it’s melted. Let simmer gently until the foam rises to the top of the melted butter. The butter will make lots of spluttering sounds and perhaps splatter a bit, so be careful.
Over the next 20-30 minutes (depending on the water content of your butter),watch the butter carefully as 3 layers develop: a foamy top layer, a liquid butterfat layer, a milk solids bottom layer. You can remove the foamy top layer with a spoon if you like, which helps to see trough to the bottom, but this is optional – it will be strained out in the end anyway.
Once the butter stops spluttering, and no more foam seems to be rising to the surface, check to see if the bottom layer has turned a golden brown colour. If so, the ghee is ready and must be removed from the heat immediately or it will burn.
Set a few layers of cheesecloth or gauze over a sterilized, heatproof container, such as a canning jar. Carefully pour the warm liquid butter through the cheesecloth into the container, leaving behind any solids from the bottom of the pan. Let sit at room temperature to cool and solidify before placing an airtight lid on the container. Store in the fridge for 1 year or, out of the fridge for 2-3 months.
