In a medium bowl, mix 1/2 cup of water with 1 tablespoon of cornflour until fully dissolved. Then, add the dark soy sauce, light soy sauce, Chinese cooking wine, sugar, Chinese five spice powder, sesame oil, and pepper. Stir well to ensure all ingredients are combined, creating a smooth sauce that will coat your dish beautifully.

Take your thinly sliced beef and place it in a bowl. Toss the beef with 1.5 tablespoons of the prepared sauce until evenly coated. Let it marinate for about 10 minutes while you gather your other ingredients, ensuring the beef absorbs all those delicious flavors.

Bring a large pot of water to a rolling boil over medium-high heat. Add your small florets of broccoli and blanch for just 1 minute. After that, throw in the egg noodles for an additional 15 seconds before draining everything in a colander.

In a large skillet or wok, heat 2 tablespoons of peanut or vegetable oil over high heat until shimmering. Add the finely chopped garlic first, stirring for about 30 seconds until fragrant. Next, toss in the sliced onion and stir-fry for another 2 minutes.

Once your aromatics are ready, add the marinated beef to the skillet. Stir-fry for about 3-4 minutes until the beef is nicely browned and cooked through.

To the skillet with the browned beef, add your drained broccoli and noodles along with the remaining sauce. Gently toss everything together for about 1.5 to 2 minutes.

Once everything has come together and is heated through, remove the skillet from heat. Serve immediately, garnishing your plate with a sprinkle of sesame seeds and chopped shallots or green onions.