Heat the oven to 180C/fan 160C/gas 4. Put the ribs fleshy-side down in a roasting tin, then pour over chicken stock. Add the star anise, soy sauce and rice vinegar. Cover tightly with foil and cook for an hour.
Meanwhile, put all the glaze ingredients in a pan with a splash of water and simmer gently until the sugar has melted.
Take out the ribs and pour away the poaching liquid. Turn up the oven to 190C/fan 170C/gas 5.
Turn the ribs over and brush all over with the glaze. Cook for another 30 minutes, brushing with more glaze regularly. Cut into sections and serve with rice, spring onion, cucumber and a sprinkle of sesame seeds.