Boil the milk in a heavy bottom pot, with few green carrdamoms thrown in, till it reduce to its half the measure. This will take around 20 minutes on medium low heat. Keep stirring.
If you want more malai or cream on top ,then keep collecting them on sides of the pan. I dont like that so I keep stirring it, that way cream will get fully incorporated into the milk and gives a delicious taste to it.