Whisk together the fish sauce, crushed garlic, shallots and sugar until the sugar is dissolved.
Mix half the sauce with the pork belly and marinate in the refrigerator for a minimum of 2 hours and a maximum of 4.
In a large bowl combine the pork mince with the egg, garlic chives and fish sauce marinade. Cover and marinate for 2 hours to let the flavours combine.
Boil a large pot of water and remove from heat. Soak the vermicelli in the water for 4 minutes, remove with tongs and refresh under cold water while separating any clumps of noodles. Cut the noodles to 15 cm lengths and coil into a large bowl for serving.
Remove the pork mince mixture from the refrigerator and with wet hands, shape into patties that are roughly 1 cm in height and 5 cm diameter. Place on a tray on parchment paper until ready to grill. Remove the pork belly as well and bring up to room temperature.
To make the dipping sauce, combine the sugar, fish sauce and rice vinegar in a small saucepan and stir over low heat until the sugar has dissolved. Add 200 ml of water.
Place the pork patties and pork belly pieces into separate BBQ grilling baskets. Cook the patties and pork belly on a hot barbecue or grill for 3 minutes a side. Check for doneness and keep warm until ready to eat.
There are many different ways to serve this dish. If you’re serving it to guests, give each one a bowl with some noodles, a pork pattie, a couple of pork belly pieces in it. Add a little of the sauce and a few pieces of carrot and radish to make it look pretty.
Place the rest of the pork on a platter. Arrange another platter with the noodles, bean sprouts, lettuce and herbs and place in the middle of the table.