Clean, peel, and cut potatoes into thick straight slices. Start by slicing it from the ends to give you round cuts. Then, slice it into thick rectangular strips.

Wash the cut potatoes with water to remove the starch.

Prepare a pan with water and let it boil. Add salt and white vinegar to boiling water.

Cook the potatoes for 5 minutes and drain.

Coat the boiled potatoes with cornstarch. Mix well until each potato slice is evenly coated with cornstarch.

Prepare a pan with cooking oil for deep-frying. When the oil is 356°F, fry the potato slices until golden and crispy. Drain extra oil after deep frying. You can also bake or air-fry the potatoes. Bake for 45 minutes at 200°C or 400°F or air-fry for 25 minutes at 200°C or 400°F. Remember to flip it halfway through the cooking time to ensure even cooking. Cook until golden brown and crispy.

Prepare a pan for stir-frying. Chop your onions, green onions, and Thai chili pepper.

Keep about 1 tbsp oil in the pan. Stir-fry the chopped red onions, chopped green onions, and Thai chili pepper until they are fragrant.

Put the fried potato slices in the pan.

Sprinkle a generous amount of salt and pepper powder. Give it a good mix to evenly spread the powder.