In a small bowl, whisk the cornstarch into the chicken stock until completely smooth.
Add the light soy sauce, dark soy sauce, oyster sauce, Shaoxing wine, sugar, white pepper, and sesame oil; whisk until the sugar dissolves.
Use right away to finish a stir-fry: Stir-fry your aromatics, protein, and vegetables over high heat until just cooked; return everything to the pan, give the sauce a quick stir, and pour it around the sides of the hot wok.
Toss and cook until the sauce boils and thickens to a glossy coat, 30–60 seconds; serve immediately.
Or cool the mixed sauce, transfer to a jar, and refrigerate up to 1 week; shake before using.