Wash and cut the scallion into 1½ inches. You can leave some greens to cut as toppings.
In a pot, add oil and scallion whites, turn the heat up to medium.
Cook the scallion whites until it's golden brown. Take out the scallion whites, turn the heat to low or off
Cook the scallion greens in the oil. Cook until the scallion greens are slightly dark and no moisture is left in it. Scoop out the greens into a bowl.
Let the oil cool down a bit.
Add soy sauce, dark soy sauce, sugar into the oil and put the heat back to medium low.
Once it starts boiling, keep boiling for about 20s.
Turn off the heat and add the scallions back in. The scallion oil is done.
Boil some water, cook your favourite wheat noodles.
Fry up an egg (optional)
Mix scallion oil (2-3tbsp) with the noodles and top with eggs. You can also toss in some preserved radishes for some extra crunch and flavour.