Peel and grate dudhi with a big hole grater.
Heat ghee in a pressure cooker, add grated lauki, and saute for 5 minutes.
Sprinkle some water and saute lauki till it shrinks, is slightly transparent, and becomes soft.
add in ¾ cup milk and mix well.
Cover the lid and pressure cook for 1 whistle on medium flame.
Release pressure naturally and open the lid.
further, add in ¾ cup sugar and mix well.
sugar melts and boils for 5 minutes or till it thickens.
Meanwhile, heat ghee in a pan, add cashew and almond. Roast for a minute. Then add raisins and roast them.
Add roasted dry fruit and khoya into lauki mixture and mix well.
keep stirring till the mixture thickens and forms a mass.
add in ½ tsp cardamom powder. mix well.
Add a pinch of green food color (optional) and mix well.
transfer dudhi halwa / lauki halwa to a small plate (or bowl) and serve hot or chilled.