First peel the bottle gourd with a peeler (with ridges preferably). Cut into half, then through the seeds and into quarters.
Grate it finely. Measure 2 cups of grated lauki.
I squeeze the excess water, it's optional.
In a heavy bottomed pan, heat a tablespoon of ghee. Add broken cashews to it and roast in medium flame until golden. Drain from ghee and keep aside.
In the same ghee, add lauki and sautee well for 2 mins. You can cook covered.
Dissolve milk powder in milk. Bring to boil.
Add it to sauteed lauki. Cook in low flame until all the milk gets thickened.
Add sugar and mix well. It will liquefy but keep cooking until it thickens. But do it in medium flame.
After it have thickened, start adding ghee little by little and keep stirring.
It will start giving whitish micro bubbles in the bottom. This is halwa stage.
Make sure not to cook in high heat as it will harden the halwa. Also take care not to change it's colour. If it caramelizes, it gets hardened as it cools.
Add the fried cashews and mix. Switch off the flame and transfer to serving bowl.