In a small bowl, mix together the sauce ingredients and set aside. Heat the oil in a large wok. Season the pork and sear in batches, then remove and set aside.
Fry the garlic until golden – about 30 secs – then add the broccoli and onions. Stir-fry for 2 mins, then add the pork and cashews along with the sauce. Keep stir-frying for another 2-3 mins until everything is hot and simmering.