1. Braai or grill the boerewors.
2. To make the quick pickle, place the sliced red onions in a big shallow bowl and add the vinegar, salt and sugar. Set aside to soften slightly for 30 minutes or longer – they’ll keep up to a week in the fridge.
3. Split and butter the rolls and add the cooked boerewors. Drain the vinegar from the onions, pat them dry on a paper towel, and add them to the rolls along with the gherkins.
4. Drizzle generously with Crosse & Blackwell Burger Sauce, and serve immediately.