Slice the pork loin into 1/8 of an inch thick slices. Marinade it with salt, white pepper, baking soda, and Chinese cooking wine. Set it aside for 15 minutes.
Combine all the ingredients for the sweet and sour sauce. Set it aside.
Combine 1 cup of cornstarch with 3/4 cup of water. Then mix with the marinaded pork thoroughly.
Bring the frying oil to 380 F. Unfold the pork slices and drop them in the oil. Fry for a few minutes. Remove it from the oil and let it rest for 10 minutes.
Bring the oil to 400 F. Double fry the pork for 1-2 minutes or until golden brown to reinforce the crust. Remove from the oil and set it aside.
Add a little bit oil to a wok along with some ginger shreds and garlic slices. Stir until fragrant. Pour in the sweet and sour sauce. Keep cooking until the sugar melts completely and the sauce starts thickening. Toss in the pork and stir thoroughly.
Garnish with some scallion shreds.