Methods

1. Break the pasta into ¼-inch pieces (about the size of a grain of basmati rice) and place in a bowl. Heat a Dutch oven or large, heavy-bottomed pot over medium heat. Add the broken pasta, reserving the bowl, and toast, stirring frequently until golden brown, 2 to 5 minutes (don’t walk away during this step, it turns from light golden to too dark and toasty very quickly!). Transfer the toasted pasta back into the bowl and set aside.
2. Combine the milk, sweetened condensed milk, and 1½ cups water in the Dutch oven and bring to a gentle boil, stirring occasionally, over medium-high heat.  Stir in the sabudana, ginger, green cardamom, and ¼ teaspoon salt (do not add before the milk has come to a boil because the enzymes in the ginger will cause the milk to curdle!). Cover, reduce the heat to medium low, and simmer, stirring occasionally to make sure the tapioca isn’t sticking to the bottom of the pot, until the tapioca is starting to turn translucent around the edges but still retains a bite, 20 to 25 minutes. 
3. Stir in the toasted pasta and continue to cook, covered, stirring occasionally, until the pasta is cooked through and the liquid has thickened so it just coats and clings to the back of the spoon, 20 to 25 minutes more (the consistency is meant to be looser than American pudding). Turn off the heat and keep covered until ready to serve.
4. Meanwhile, make the topping. Heat the ghee in a skillet over medium heat. When melted, add cashews, stirring to coat the nuts in the oil. Cook, stirring occasionally, until the cashews start to turn light golden in spots, 2 to 4 minutes. Stir in the golden raisins and remaining ⅛ teaspoon fine sea salt, and continue to cook until the raisins start to plump up and turn a shade darker in spots, 1 to 3 minutes more. Transfer to a shallow bowl and let cool completely.
5. To serve, ladle the warm payasam into small bowls, and top each with a couple spoonfuls of the ghee-nut-and-raisins mixture.