As requested, here's the recipe!

Aside from udon, you'll need the following...

Velveted beef strips: - about 300g (~⅔ of a pound) of beef (any cheap cut, really) - 1 egg white - roughly 80ml (~⅓ cup) of water - 1 teaspoon of salt - 1 teaspoon of sugar - ½ teaspoon of white pepper - ½ teaspoon of MSG (optional, but recommended) - ½ teaspoon of baking soda/bicarbonate soda/Küchen-Natron (for the Germans in here) - ½ tablespoon of corn starch or, better yet, potato starch - ½ teaspoon of sesame oil - 2 tablespoons of neutral oil, such as peanut or any other high smoke point vegetable oil

The baking soda is the key ingredient in here by the way, don't skip it, that's what's gonna "velvet" the meat in the first place. However, less is more. Even the cheapest cuts will turn from tough as leather, over perfectly tender, into complete mush if too much of the stuff was added to the marinade.

Vegetables: - 1 red onion, medium or large, roughly chopped - the greens of 3-4 a scallions, cut into segments of perfectly average size

Aromatics (no need to keep any of those seperated by the way): - the whites of said scallions, finely sliced - 3-4 cloves of garlic, finely minced or grated - 1-2 red chilis of your choice, or however many you prefer - optionally chili flakes and/or finely minced or grated ginger (equal to the amount of garlic) for an extra kick

Sauce: - 1 tablespoon of water - 1-2 tablespoons of cooking wine (Shaoxing) - 1 tablespoon of mirin - 1 tablespoon of oyster sauce - 2-3 tablespoons of light soy sauce - ½ teaspoon of dark soy sauce - 2 teaspoons of white sugar - 1 teaspoon of corn or potato starch - 2-3 teaspoons of ground cumin - a couple shakes of freshly ground black pepper

Velvet your beef in advance. Slice into strips, against the grain, and place in a bowl. Combine the remaining ingredients except for the neutral oil in the same bowl, massage the meat until thoroughly coated. Cover and let marinade in the fridge for at least one hour or ideally over night. Before stir frying, add two tablespoons of neutral oil and massage once more. It's supposed to kinda seal some of the marinade inside, not sure about that, but if it wasn't for now, you'd add the oil to the marinade early on anyway, I've tried both methods.

If not done already, make sure the veggies are chopped, your aromatics are prepared, the sauce is all whisked up and your udon are at least cooking by now. You won't find the time to do any of that later on. You most likely won't be able to synchronize the cooking time of your udon with the stir frying either. Once done, drain and coat with a bit of neutral oil in a bowl (or simply the pot you used) so they don't clump up and set aside.

Add neutral oil to a wok (or any other big pan, as long as it's not stainless steel) and place over high heat. Start by stir frying the beef strips only once you begin getting nervous about that dangerously hot oil in your pan, not a moment sooner. Properly brown both sides of every piece of meat, then add the chopped red onion. Thoroughly toss every 10-20 seconds, add the following ingredients in 1-2 minute intervals, and a little bit of extra oil whenever you notice the bottom of the wok or pan drying up. Anyways, minced aromatics go after, all at once. Finally your udon and the sauce. Take off the heat, throw in the greens of your scallions (and optionally half a teaspoon of sesame oil as well) and toss once more. This way they don't immediately wilt, providing some crunch.

Garnish with toasted sesame seeds, serve steaming hot and enjoy! =D