Barbecued pork fillet with Vietnamese caramel sauce

To make the sauce, combine the sugars and 2 tablespoons of water in a small saucepan. Cook over low heat, stirring until the sugars have dissolved. Up the heat to medium and continue to cook until the sauce reduces (about 2 minutes).
Remove the sauce from the heat and transfer it to a jug to cool.
When cooled, add the oil, fish sauce, lime juice and chili and mix it through.
To prepare the marinade for the pork, mix together the fish sauce, sugar and garlic in a bowl then add the pork fillet to the bowl and toss it around until it is coated. It's easier to cut the fillet in half first. Cover the bowl and refrigerate it for 10 minutes while the barbecue heats.
Cook the pork on the barbecue turning so that each side gets nice char lines. It should take 12-16 minutes to be cooked through.
Leave the pork to rest on a chopping board for 5 minutes and then slice it up.
Place the pork slices on a serving platter and dress with the caramel sauce.