In every Indian household milk is always boiled before use. While boiling milk a layer of fat/cream is formed on the top. Scoop out the cream from the milk and store it in air tight box in fridge. I collect milk on day to day basis and store it until I have enough(about 2 cups) before I start the process of making ghee. This will take a few days, few days of collecting milk cream or fat.
Once you have enough fat/cream collected take out the milk cream from fridge. Whisk 2 teaspoon curd to the milk fat. Leave it in room temperature for 1 or 2 hours. Whisk one or twice during this time.
Transfer the milk cream into a blender. Add ice cold water little at a time and pulse it for few times. Add water again and pulse. Do this many times and keep pulsing the blender. After about 15 minutes you will start seeing butter getting churned. Continue adding ice cold water again and pulse, after a few more times, butter should be completely separated from the cream.
Pour the churned butter into a sieve or muslin cloth. Rinse freshly churned water a few times to get rid of all the smell. If you are planning to store butter for your homemade parathas or rotis, then this is it. Store the well rinsed butter into a box in fridge after all the water is drained out well.
To continue to making ghee, heat a pan(preferably non stick pan) and pour the butter into the pan. Cook on low heat with constant stirring. Make sure you keep stirring at regular intervals, else butter will start to burn from the bottom of the pan.
After about 40 minutes you will start to see ghee(clear oil like consistency) and milk solids start to settle at the bottom. The aroma of ghee indicates that ghee is ready to be strained.
Strain ghee through a sieve. Do not throw away the milk solids collected. If you stirred continuously, the milk solids will resemble brownish khoya. You can use that you make sweets like peda.
Store the ghee in air tight container at room temperature. This ghee stays good for very long time even for 6 months(well if it lasts that long) at room temperature.