Prep the potatoes: Grate the potatoes on the small holes of a box grater. Place the shreds in a bowl of cold water and swish to release starch. Drain through a sieve, then rinse until the water runs mostly clear.

Extract moisture: Transfer the grated potatoes to a clean kitchen towel. Twist and squeeze out as much water as possible. The drier the potatoes, the crispier your noodles will be.

Make the dough: In a mixing bowl, add the squeezed potatoes, potato starch, baking powder (if using), salt, and pepper. Mix with your hands. It should form a cohesive, slightly tacky dough. If it’s crumbly, add 1–2 teaspoons of water. If it’s too wet, add a little more starch.

Shape the noodles: Lightly dust your work surface with starch. Pinch off small portions and roll into thin ropes about the thickness of spaghetti or udon, depending on your preference. Cut into 3–6 inch lengths. Keep them covered with a damp towel so they don’t dry out.

Par-cook in boiling water: Bring a pot of salted water to a boil. Drop in the potato noodles in batches. They’ll sink, then float as they cook—about 1–2 minutes. Once they float, cook 30 seconds more. Scoop out and drain well. Toss with a tiny drizzle of oil to prevent sticking.

Make the seasoning: In a small bowl, mix soy sauce, vinegar, sesame oil, and minced garlic. Set aside. You can add a teaspoon of sugar if you like a hint of caramelization.

Pan-fry: Heat a large nonstick or well-seasoned cast-iron skillet over medium-high heat. Add 1–2 tablespoons of neutral oil. Spread the noodles in a single layer. Don’t crowd the pan. Fry undisturbed for 2–3 minutes until the bottoms turn golden and crisp.

Toss and flavor: Flip or gently toss the noodles. Add the sauce around the edges of the pan so it sizzles. Cook another 1–2 minutes, allowing the sauce to glaze and the noodles to crisp in spots.

Finish: Add scallions and toss briefly. Taste and adjust salt or vinegar. Serve hot with chili crisp or sesame seeds if you like a kick.