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.