1. Heat the oil in a wok over high heat. Add the cashews and stir-fry for about 30 seconds or until lightly browned. Using a slotted spoon, transfer to paper towels.

2. Add the tofu and stir-fry about 2 minutes, or until golden. Transfer to the paper towels. Add the onion and carrots and stir-fry for 2 minutes, until crisp-tender; add the red pepper, celery, and mushrooms and stir-fry for 3 minutes more. Finally add the bean sprouts and stir-fry for 2 minutes, until hot. Always keep the heat under the wok high so that the vegetables sear quickly without overcooking.

3. Meanwhile, mix the stock, soy sauce, and chile sauce in a small bowl. Add the cornstarch, and stir to dissolve. Return the cashews and tofu to the wok and add the stock mixture. Stir until the sauce is bubbling and lightly thickened. Serve hot.