Put oil into a wok and add cashew nuts. Heat up the oil and deep-fry cashew nuts until lightly golden brown. Dish out and drain on kitchen paper towels.
Leave 1 tablespoon oil in the wok; lightly brown garlic and ginger. Add carrot and fry well.
Put in celery and cloud ear fungus. Toss to combine well. Pour in sauce ingredients and add mushrooms. When mixture boils, thicken with cornflour mixture. Sprinkle in cashew nuts, spring onion and chilli. Fry briskly over high heat to combine.