Soak the cashews in hot water for atleast 15 minutes.
In the meanwhile, cut the skin, remove the flesh or pumpkin guts and separate the seeds, keep it aside.
Roughly chop the pumpkin into thick chunks. Give it a good rinse.
Heat water in a pan, add the pumpkin and cook it until its soft. Switch off the flame and allow the pumpkin to cool.
While the pumpkin cools, drain the water from the cashews and grind it into a smooth paste. Add couple of spoons of water, if required.
Once cool, use an immersion blender or a mixer grinder jar and blend into a smooth paste. Do not add any water.
Put the same pan back on the heat, add oil, finely chopped garlic and onions. Saute until they have caramelized or golden brown.
Now add the pumpkin puree, herbs, salt to taste, smoked paprika powder, kashmiri red chilli powder and mix well until it thickens slightly.
To the pumpkin mixture, add the ground cashew paste and mix well. Ensure the flame is low at this point. We don't have to boil the mixture for too long. Add nutmeg powder and switch off the flame.
Your Pumpkin sauce is ready. Either cool it and then transfer it to the refrigerator or freeze it for use later.