Mix ketchup, soy sauce, honey, ginger, garlic, sherry, star anise, ketjap manis, and rosemary in a dish.
Add the ribs to the marinade and chill for up to 24 hours if possible.
Transfer ribs and marinade to a deep pan and cover completely with water.
Simmer the ribs over medium heat for 45 to 60 minutes until tender.
Preheat the grill and reduce the cooking liquid on the hob until it reaches a sticky consistency.
Grill the ribs for 8 minutes per side while basting with the reduced sauce.
Preheat the oven to 200°C and bake pricked, oiled potatoes for 40 minutes until soft.
Cool the potatoes, cut into quarters, trim the flesh to 5mm thickness, and brush with oil.
Toss the oiled potato wedges in a mixture of polenta, parmesan, rosemary, salt, and pepper.
Bake wedges on a wire rack for 30 minutes at 200°C, turning halfway through.
Cut ribs into portions, garnish with spring onions, and serve with sides.