Soak the noodles in room temperature water per package instructions.
Make the sauce by pounding 5 cloves of garlic and 3 slices of ginger in a mortar until quite fine and transfer to a mixing bowl.
Add the sugar, ground white pepper, soy sauce, black soy sauce, oyster sauce, and water and mix. Set aside.
Cut the soaked noodles so that they are easier to eat when cooked and drain the water.
Pour the sauce over the noodles and toss. Add the shiitake mushrooms and toss again.
Add the oil and 8-10 ginger slices to a heavy-bottomed pan or pot (non-stick, if possible) and heat over medium heat. Once the oil is sizzling, add the noodles that have already been mixed with the sauce and mushrooms and place the shrimp on top. Cover and cook for about 5 minutes.
Open the lid and stir or toss the noodles to make sure the sauce is thoroughly distributed.
Add the chopped Chinese celery. Then, cover and cook for another minute before turning off the heat and serving.