Soak your rice for 15 to 20 minutes beforehand, drain and rinse well a few times (to get the extra starch off).
Bring 1 liter of whole milk slowly to a boil, and once it's close, prep your rice and cardamom (next two steps).
Put the soaked rice in your mortar bowl and use the pestle to kind of crush or grind the rice into small pieces. You don't have to be obsessive about this and you're not looking to crush it into powder. Just break it up...this makes a huge difference in the overall texture (see notes if you don't have a mortar and pestle).
Crush the green cardamom pods in the mortar, remove the skins, and then grind up the little black seeds with your pestle.
As soon as the milk has come to a boil, turn it down to a simmer and add the crushed rice and ground cardamom, and a solid pinch of salt.
Cook on slow heat, stirring frequently...it could be 40-45 minutes or up to an hour, but the key is not to rush it or turn it up too high. Basically, you don't want to scald the milk (blech). Just be patient and keep stirring it every couple minutes.
Once it's thickened appropriately and the rice is really soft (at least 35 minutes, but likely 45 or longer), add the sweetened condensed milk and stir in. You can add up to 200ml more of milk at this point to loosen it up a bit (see my notes).
Go ahead and add your golden raisins and the nuts. If your golden raisins are on the chewy and dry side, you could even add them a bit earlier to make them soft and juicy.
Once your textures are perfect and it's the thickness you want, remove from the heat and add a couple drops (LITERALLY JUST THIS MUCH) of rose water or orange blossom water. I think the rose water is more traditional but I've done both and they're equally delicious.
Serve hot and fresh, warm, or room temp (my preference) and top with some more nuts.