Slice open the hotdogs.
In a pan over a medium heat, fry the onion in the olive oil for about 5-10 minutes, until soft and golden.
Add the rest of the sauce ingredients (except for the water) and simmer for 10 minutes, stirring often to make sure it doesn't burn. If the sauce gets too thick for your liking, or starts to burn, stir in a little water.
After simmering for 10 minutes the sauce is ready to serve. Set it aside until you have finished braaing the boerewors.
To braai the boerewors, place it in a hinged grid and close the grid. Braai for 4 minutes on one side over very hot coals. Turn the grid once, then braai for 4 minutes on the other side. You will know that the boerewors is ready when the skin is brown in most parts and grey in others.
Remove the boerewors from the fire. The juices on the inside of the boerewors should be bubbling. Wait for the bubbles to relax, then break or cut the boerewors into 6 pieces. Place each piece of boerewors in each hotdog roll and top with a few spoons of monkey gland sauce.