Heat your wok back up to medium heat, add in about a Tbsp of oil then add in your marinated pork. Cook both sides of the pork strips to about 80% done then remove it from the wok. The pork should look mostly white with barely any pink visible. Don't worry we'll be adding it back in to our sauce later when we're making it.
Next add in about a tsp of oil to the wok, heat it up to medium heat and then dump your onions in. Cook the onions for about 1-1.5 minutes then add in the minced garlic followed by the white part of the green onions, stir-fry that for about 20 seconds, followed by adding in your mushrooms. Continue stir-frying this for about 1 minute.
Now add in your sauce mixture. Mix the sauce well and then add in your chicken stock to the wok and mix everything well together. Turn up the heat to about medium-high and once you start to see the sauce simmer, add in your cornstarch slurry, making sure to stir the wok with your spatula while you slowly pour in the cornstarch.
Once the sauce has become thickened, add back in your pork slices from earlier followed by the beansprouts. Mix everything well together for about 30 seconds. Turn off the heat, add in the green parts of the green onion you cut earlier. Mix everything together for another 30 seconds and transfer the sauce out of the wok.
Pour the sauce right on top of the crispy pan-fried noodles when you are ready to serve the dish.