Peel, core and chop the apple into cubes. Also, peel, cut in to half, deseed and chop the pumpkin into cubes.
Pressure cook apple and pumpkin pieces along with the cinnamon stick in instant pot using pot in pot method on manual high pressure 6 mins and natural release for 5 mins and then quick release the pressure. Alternatively, you can also cook them in a stovetop pressure cooker until you get 3 whistles or in a pot of water on the stovetop until they are soft enough to mash or puree. TIP: When cooking pot in the pot in an instant pot or stovetop pressure cooker, put ⅓ cup of water in the vessel of apple and pumpkin pieces and 1 cup of water in the main pot of the instant pot or on the stovetop pressure cooker to build pressure.
Now strain the apple and pumpkin pieces by just placing them in a strainer to remove any water and then mash them in a bowl or plate until smooth. Keep the cinnamon stick aside as we need it again. Alternatively, you can blend them in a blender without the cinnamon stick.
Heat a pan and add 3 tbsp of ghee.
Add the mashed apple and pumpkin puree along with the cinnamon stick to the ghee and cook for 4 to 5 mins while stirring occasionally.
Now add 1.5 cups of sugar and stir well. I used powdered white sugar (confectioner's sugar) here because that is the only white sugar I have today. You can add any kind of sugar that you use regularly.
Let it cook for 5 mins until sugar is well dissolved and halwa starts thickening.
Now add 1.5 cup of khoya(khoa) and stir in well. Cook for 2 to 3 mins until khoya(khoa) is well combined with the halwa.
Now add ¾ tsp ground cinnamon , 1.5 tsp vanilla extract and 1 tsp ground cardamom ( elaichi powder ) and stir well.
Finally add the saffron milk ( 6 or 7 saffron strands soaked in 2 tbsp warm milk ) and cook for another 2 mins until the halwa comes together beautifully. Discard the cinnamon stick.
Garnish with ghee roasted nuts of your choice.