Wash the potatoes thoroughly, bring them to the boil in a saucepan with water, cover and cook over a medium heat for about 20 minutes. Then drain, quench and peel. Cut the potatoes into slices.
In the meantime dice bacon finely. Peel and finely dice the onion. Leave the bacon in a pan, add the diced onion and fry until transparent. Deglaze with stock and vinegar, bring to the boil and simmer at low heat for 2-3 minutes.
Season to taste with salt, pepper and sugar. Pour over the potato slices and leave to stand for about 30 minutes. In the meantime peel red onions and slice them into very fine rings. Wash the maties and pat them dry.
Spread the inside with cream cheese. Spread onion rings evenly on top. Roll them up and fix them with wooden skewers. Arrange potato salad and matie rolls on plates. Serve garnished with rocket.