To a heavy bottom pan, add whole milk on medium-high heat.

After around 5 minutes when it warms a little, add heavy cream to it.

Let the mixture come to a boil and then reduce the heat to medium.

Let the milk simmer on medium heat for around 30 minutes, keep stirring it in between, you don't want the milk to get stuck to the bottom of the pan.
After about 30 minutes, the milk will look quite thick, at this point add crumbled khoya and mix. Keep mixing this the khoya dissolves, this will take 5-7 minutes.

Once the khoya dissolves, add the sugar and mix till the sugar dissolves.
Then add the crushed nuts. I crushed these using blender two pulses.

Add milk powder (if using) and mix. Simmer for 5 more minutes. In all I cooked the milk for around 50 minutes, it should get really thick by the end of it and it will continue to thicken as it cools down.

Remove pan from hear and cardamom powder and mix.
Let the mixture cool down completely.
Once the milk has cooled down completely Then transfer the milk into the bowl add flavour content one by one pour into kulfi molds or any other container of your choice. Cover and freeze till completely set, around 6-8 hours.