In a wok or large pot, heat the oil over medium heat. Carefully add the dry rice vermicelli, frying them until they puff up and turn a light golden color, about 2-3 minutes. Use a slotted spoon to transfer them to a paper towel-lined plate to drain.

In a separate pan, heat 2 tablespoons of neutral oil over medium heat. Add the sliced shallots and sauté until they turn a caramelized golden brown, about 5-7 minutes.

Push the shallots to one side of the pan and crack the egg into the empty side, scrambling it until cooked before mixing it with the shallots.

In the same pan, add the palm sugar to the shallots and egg mixture. Stir in the fish sauce, table salt, tamarind paste, lime juice, and lime zest. Cook, stirring continuously, until the mixture reaches 240°F and becomes slightly thick.

Before removing from heat, add the fried noodles to the sauce, tossing them gently until they are evenly coated.

Line an 8x8 inch baking pan with parchment. Layer the mixture into the pan, sprinkling with cashews and pumpkin seeds as you go. Press down firmly with a spatula to pack everything together.

Allow the mixture to cool completely in the pan. Once cool, cut it into bite-sized pieces and store in an airtight container.