Boil the potatoes as jacket potatoes, peel them, let cool down a little and cut into slices. Leave the smoked bacon in a non-stick pan and add to the potatoes. Add vinegar, mustard, sugar, onion, a little salt and pepper to the hot vegetable stock and pour everything over the warm potato slices while still hot. Let it steep for at least 3 hours and then season with salt and pepper.
As a lower-fat variant, I use lean, raw ham cubes, which I then add to the salad without stewing them.