Slice the flank steak against the grain (about ¼ inch thick slices). Put the sliced steak into a bowl with the ingredients for the marinade: soy sauce, sugar, cornstarch, baking soda, and water. Mix well, then add neutral oil to seal in the marinade. Mix and set aside while you prep the other ingredients.

Use this down time to get all your other ingredients sliced and ready: slice the onions and ginger, crush the garlic, chop scallions into 2-3 inch pieces, and wash your bean sprouts.

Prepare your noodles by taking them out of the package and separating them by hand or massaging them gently — be careful, the fresh ones are fragile!

In a bowl, prepare the sauce for the noodles: mix together light (regular) soy sauce, dark soy sauce, sugar, and oyster sauce.

Heat up a big skillet (or wok if you have one) to medium-high heat. Add 1 tbsp of oil. Once the pan is hot, add your marinated slices of beef in one layer. After 1-2 minutes, flip each slice. Cook until both sides are brown and slightly charred (shouldn’t be more than a few minutes). Remove the beef from the pan.

Add a bit more oil to the pan, then add your aromatics: garlic, scallions (white parts only), ginger, and half of the sliced onions (we’re adding half now to flavor the oil and to develop caramelization — save the rest for the end). Cook for 1 minute or until slightly charred.

It’s time to add your noodles! I recommend using chopsticks and/or a wooden spatula to stir fry the noodles (instead of any sharp or metal utensils). With a gentle scooping motion, lift the noodles from the bottom from the pan and up to stir — this keeps the noodles in tact.

Cook noodles for a minute, then add Shaoxing wine (this should deglaze the bottom of the pan), and mix everything together. Then add the sauce for the noodles. Mix gently with the same lifting motion, and make sure every noodle is coated in the sauce. This should only take a minute or less.

At this point, taste the noodles! If it's not salty enough, add more soy sauce. If it's on the saltier side, add a bit more sugar to balance it out. If you like the color of your noodles darker, add a touch more dark soy sauce.

Now the final steps: add the cooked beef, green parts of the green onion, bean sprouts, rest of the onion (we’re adding the rest now to get the flavor from fresh onion — slightly raw and pungent, which contrasts against the rest of the dish), and the sesame oil. Mix well, without breaking up too much of the noodles. Once the green onions and sprouts have softened a bit, it’s done!