Rinse then soak the fermented black beans for 5 minutes in cold water, then drain and roughly chop.
Meanwhile, heat the wok and slice the celery and spring onions into 1cm slices on a diagonal bias.
When the wok is smoking hot, add the celery and splash in a quarter cup of water. Allow this to evaporate on a medium-high heat (2-3 minutes), then splash in the oil and let the celery keep colouring and softening for another 3 minutes, tossing about frequently.
Mix up the sauce ingredients in a jug or bowl, and stir through the chopped black bean. Set aside.
Add the spring onion to the hot wok, stir fry for another 2 minutes, the cashews and stir-fry for 2 more minutes.
Give the sauce one more stir and pour it over the veg in the wok, letting it thicken up for a minute or so, then switch off the heat.
Serve over rice, or as a handy side.
