In a small bowl, combine the stock with the soy sauce, sherry, sugar, cornstarch slurry, vinegar and sesame oil. Stir to dissolve the sugar.
In a medium saucepan, heat the peanut oil until shimmering. Add the ginger and crushed red pepper and cook over high heat, stirring, until fragrant and golden.
Add the stock mixture and boil over high heat until thickened and glossy, about 1 minute.
Note/Ideas: I usually add some garlic and some fresh orange juice instead of all that stock and 1/4 teaspoon of salt - I think this is really nice because it gives you a lot of sauce - I don't like a dry stir fry, especially over rice.