Peel 450g potatoes and slice them into thick pieces. Steam the pieces for about 25 minutes until they are fork-tender.

While still hot, mash the potatoes into a smooth puree in a bowl. Don't forget to discard any water released during steaming to ensure the dough isn't too wet.

Add 200g potato starch to the mashed potatoes and knead until a uniform dough forms. If the dough feels dry, add a little water; if it's sticky, sprinkle in more starch.

Divide the dough into small pieces, roll each into a ball (about 20g each), and flatten them into button shapes using the bottom of a round object like a bottle.

Bring a large pot of water to a boil. Gently add the button noodles and stir occasionally to prevent sticking.

Cook until the noodles float to the surface. Remove them with a slotted spoon and transfer immediately to a bowl of ice water. Let them cool for a few minutes to enhance their chewiness.

Drain the cooled noodles and place them in a large bowl. Add 10g minced garlic, 5g chopped scallions, 1 tsp sesame seeds, and 1 tsp chili powder. Drizzle 3 tbsp hot oil over the top to release their aroma.

Pour in 15ml light soy sauce, 2 tbsp aged vinegar, 2 tsp oyster sauce, and 1/2 tsp sugar. Toss everything until the noodles are evenly coated in the dressing.