First toast your green cardamom pods on a low heat for 2-3 minutes, then transfer to a pestle and mortar
Lightly bash the pods open and remove as much of the green husks as you can and grind the cardamom to a fine powder
Place the milk into a saucepan and add your jaggery or sugar. If using jaggery try to break this apart or roughly chop to help it dissolve more readily
Add in the cornflour to the saucepan and immediately whisk to dissolve completely, no lumps should remain
Add the vanilla, cardamom, and turmeric (if using). Break the saffron strands up between your palms or fingers and add this too. Whisk to combine
Place the mixture on a low heat and continue to mix for several minutes until the jaggery/sugar has completely dissolved
Then turn the heat up to a medium-high heat and switch between a whisk and a spatula and continuously stir. It will take around 4-5 minutes to start thickening, but will thicken very rapidly. The final consistency should be thick but pourable
Once the custard has thickened, turn the heat back down to low and add in the butter. Mix until the butter has been incorporated
Transfer the mixture equally to 4 ramekins whilst the mixture is still hot, then allow the custard to cool at room temperature for 1 hour
After 1 hour, cover each ramekin with a clingfilm or a lid and place into the refrigerator for a minimum of 6 hours