Melt your butter over medium-high heat. Once it has come to a simmer turn your timer on for 4 minutes, keeping an eye on the butter to make sure it doesn't start to brown. Once the timer has gone off remove the butter from the heat.
Pour the butter into a glass or plastic container with a tight-fitting lid. Place the container in the fridge overnight.
Remove the container from the fridge. Using a spoon scrape the top white milk solids off the top of the butter and discard the milk solids.
Store in an airtight container in the fridge. Your ghee will solidify again once it has cooled and then you just cook with it like you do butter.