Put unsalted butter in a crockpot, set it on low and leave the cover off.
Walk away and check it in 6-8 hours, closer to 6 if you want a lighter colored ghee.
You can skim off the foamy top layer if you want; it will eventually sink to the bottom.
Strain through cheesecloth or a fine meshed strainer.
Store in a glass jar on the counter or refrigerator.