Begin by bringing a pot of water to a rolling boil. Submerge the chow mein egg noodles in the boiling water and let them soak for 30 seconds to 1 minute until just tender. Drain the noodles in a colander and set them aside.

In a mixing bowl, combine dark soy sauce, regular soy sauce, oyster sauce, fish sauce, granulated sugar, and water. Whisk the ingredients together until the sugar fully dissolves.

Heat a wok over medium-high heat and add a splash of corn oil. Toss in chopped yellow onions and the white parts of green onions. Sauté for about 1 minute or until the onions are translucent.

In the same hot wok, add more corn oil, add the drained chow mein noodles, pressing them evenly to ensure they crisp up nicely. Fry for about 2 minutes, then carefully flip the noodles and crisp the other side.

Return the sautéed onions and bean sprouts to the wok. Pour in your sauce mixture over the crispy noodles. Gently toss everything together using tongs for 1-2 minutes until the noodles absorb the flavors.

Remove the wok from heat and drizzle the sesame oil over the chow mein. Toss everything one last time to incorporate the oil and serve immediately.