Pour away most of the fat from the duck leaving about 1tbsp of duck fat with all the lovely juices.
TOP TIP: Reserve the rest of the fat to make gorgeous roast potatoes.
Place back on the hob over a medium high heat.
Sprinkle the 75g sugar evenly over the base of the pan and cook until a tan caramel is formed. Don't burn the sugar or will be bitter.
Very quickly add the rice vinegar for the sauce, be careful as it will spit.
Stir to combine and then pour in the rum and if brave enough, set alight. If not just reduce until syrupy again.
Add the passionfruit and the stock to the pan and stir through.
Bring back to the boil and reduce until it just coats the back of the spoon.
Taste and season with salt and pepper.