Heat the butter in a small, sturdy pan and cook over a low heat without stirring for 15-20 mins, or until the milk solids start to brown and the butter is golden. Turn the heat off and leave the pan undisturbed for a few minutes.

Line a metal sieve with muslin or strong kitchen paper, and place over a heatproof bowl. Pour in the melted butter, taking care to leave the browned milk solids in the pan. Leave for a few minutes to drip into the bowl, then transfer to a jar. Because ghee has no moisture or milk solids, it will keep for up to three months at room temperature, but can also be stored in the fridge for extra longevity.