Peel and cut large potatoes into one bite size pieces or if you use small baby potatoes, cook them directly. Simmer for around 12 to 15 minutes until the potatoes are just cooked so you can easily insert a chopstick without breaking the potatoes. Optional: remove the skins of the small potatoes
Heat around 1 and 1/2 tablespoon of cooking oil in pan, add potatoes to fry until crispy and golden.
Transfer the potatoes to the edges of the pan and add another 1/2 tablespoon of cooking oil in center and fry garlic, ginger and scallion until aromatic. Add red onion and continue frying for 2-3 minutes until the red onion becomes soft too.
Sprinkle chili oil, salt, cumin power and red pepper powder if you are using. At last, mix coriander stem and chopped green onions.
For those who love hotter version, simple serve with dried chili powders. You can simple serve with a mixed chili powder.