Heat 2 tablespoon of ghee in a heavy bottom pan .
Add grated ash gourd and mix well and cook on a medium heat.
Once water content dries up , add milk and continue to cook .
When ash gourd is completely cooked , add in grated khoya .
Mix well everything so that khoya blends well with ash gourd.
Make some place at the centre and add in 2 tablespoon of Ghee.
Add cashew pieces at the centre and fry in ghee till it looks golden in colour. Alternatively you can roast cashews separately and add it the halwa at last.
Mix everything and add in sugar .
Stir everything such that sugar melts completely and starts to bubble.
Once it starts to get halwa consistency ,turn off the flame.
Add cardamom powder , saffron strands and a teaspoon of ghee.
Mix well together and serve. It can be served either warm or cold.