Use only unsalted butter. Salted butter leaves a bitter after-taste of remnants of salt and does not taste very good
Butter obtained from buffalo milk can also be used. You will get a white colour end product
Always keep an eye on the melting butter. The milk fat solids can very quickly stick to the bottom of the pan and burn
After the ghee is done, there will be a thin brown layer of milk solids left behind. Do not discard this, use it to make sweets or heat water in this pan and use it to make upma or rasam/saaru
Remember the ghee keeps cooking even after it is removed from heat till it completely cools down. It took me around 30 mins to get the desired colour, consistency of ghee