Add the potatoes to a cast-iron or potjie pot, cover with water, place on the braai and bring to the boil.
Boil until tender.
In a cast-iron pan, heat 2 Tbsp oil (30ml) over medium coals, add the onions and brown sugar and cook until the onions are softened and sticky (about 10 -12 minutes), stirring regularly to avoid burning.
Remove from the heat and set aside.
Drain the potatoes and set aside.
Add the potatoes to a heatproof roasting dish or foil roasting dish and drizzle with 1 Tbsp (15ml) oil and season generously with Spur Classic Biltong Spice.
Place the dish over the medium-hot coals and roast, tossing regularly, until golden and crisp.