Place the 500 g Spunta potatoes in a large saucepan, cover with salted water, and boil until very tender, about 20 to 25 minutes.

Drain the cooked potatoes thoroughly in a colander, then peel them while still warm.

Mash the peeled potatoes into a very smooth puree using a potato masher.

Add the 1/2 teaspoon salt and 150 g potato starch to the mashed potatoes, then mix evenly.

Pour in the 120 ml warm water and knead the mixture until it forms a smooth, flexible dough.

Divide the dough into manageable portions, then roll each portion into long noodle-shaped ropes.

Arrange the potato noodle ropes on a lightly floured baking sheet, spacing them apart to prevent sticking.

Fill a large saucepan with salted water and bring it to a rolling boil.

Lower the potato noodles into the boiling water and cook for 2 to 3 minutes, until they float to the surface.

Drain the cooked noodles in a colander, then rinse them briefly under hot running water to keep them from sticking.

Combine the 2 tablespoons soy sauce, 2 tablespoons peanut butter, 2 tablespoons gochugaru, and 1 1/4 teaspoons sugar in a mixing bowl.

Add the 2 tablespoons grated fresh ginger, 2 tablespoons minced garlic, and 1 sliced spring onion, then stir the sauce mixture well.

Heat the 3 tablespoons neutral oil in a small saucepan until it begins to shimmer.

Carefully pour the hot oil over the sauce mixture, then stir until the ingredients are fragrant and combined.

Toss the warm potato noodles with the spicy peanut chili oil, then garnish with a pinch of roughly chopped fresh coriander before serving.