Peel bottle gourd, cut into half, remove seeds, wash and then grate. Boil in water until soft, strain and then squeeze to remove excess water.
Heat ghee in a kadai, add cashewnuts and sauté till lightly browned. Drain and keep aside.
Add boiled bottle gourd to the same ghee, cook for few minutes and keep aside. Bring milk to a boil, then simmer till it is reduced to three-fourths and add the cooked pumpkin. Stir to mix well. Add sugar. Cook till sugar dissolves and kheer is semi-thick. Mix in green cardamom powder and kewra water.
Pour into individual serving bowls, garnish with browned cashewnuts and serve hot or cold.