Peel off the shell from the shrimps and devein. Set aside.
Cut the bok-choys and eringi mushrooms to bite sizes. Set aside.
Mix the yakisoba seasoning and oyster sauce with water. Set aside.
Heat vegetable oil in a frying pan and add in the noodles to stir-fry. Let the noodles turn slightly brown and loosen the noodles. Place the noodles on a plate.
Heat sesame oil in a frying pan and cook the shrimps. Add in bok-choy and eringi mushroom. Stir-fry the vegetables and add in the seasoning from Step 3. Simmer.
Stir in the slurry (potato starch dissolved in water) to thicken the gravy.
Pour the gravy, shrimp, and vegetables from Step 6 to the noodles. Enjoy!