For the sauce:
To make sauce, combine water and sugar in a saucepan over medium heat, stirring until dissolved. Add plums, cinnamon, star anise and ginger, stir to combine. Bring mixture to the boil, then reduce heat to medium-low and continue to simmer, covered, for 6 minutes or until plums are tender.
Add fish sauce and vinegar, stir to combine. Remove from heat and keep warm.
For the pork:
Preheat oven to 180°C fan-forced. Combine five spice, pepper, oil and salt in a shallow dish. Coat pork cutlets in marinade. Heat a large non-stick ovenproof frying pan over medium-high heat. Cook cutlets for 2 minutes each side, then transfer to oven for a further 5 minutes. Remove from oven, transfer to a plate, and cover loosely with foil. Allow to rest for 5 minutes. Serve pork with plum sauce, broccoli and steamed rice.