Peel to remove the outer skin of the bottle gourd. Discard the white pulp and the seeds. Grate the firm green part.
Transfer grated bottle gourd to a muslin cloth. Squeeze tightly to remove all the water from the grated bottle gourd. Set it aside.
Next heat ghee in a frying pan. Add the grated bottle gourd and fry over low heat for 5 - 10 minutes. Keep stirring to fry evenly. This step ensures to remove all the water from the grated bottle gourd. Turn off the heat.
Meanwhile, in a heavy bottom saucepan heat milk. Add the cardamom powder and stir to combine. Let the milk come to a boil once and then reduce the heat to low.
Allow the milk to simmer over low heat till it reduces to half the original amount.
Add the grated lauki and cook till the milk thickens. Keep stirring continuously. The kheer will become thick and creamy.
Add sugar, saffron, and cook for 5 more minutes. Turn off the heat.
Garnish with sliced pistachio before serving.
Serve Lauki Ki Kheer chilled or warm.