During my time in England, I have discovered a way of making extremely delicious potato salad by using sweet potatoes and vinegar. Here it is.
2.5 pounds of white potatoes (about 12 small and medium)
1.5 pounds of sweet potatoes (3 or 4)
3/4 cup or 150 ml sour(ed) cream
an equal amount of mayonnaise
Cube the white potatoes and boil them until soft. Meanwhile, liberally stab and then microwave the sweet potatoes about 10 minutes until thoroughly soft.
Scoop the hot orange potato part out of the sweet potatoes into a bowl. Mash them and then mix in the sour cream and mayonnaise until it is smooth and creamy.
Drain the white potatoes and then pour vinegar liberally all over them. Stir and repeat until you have poured in a lot of vinegar. I have poured in more every time I have made this recipe, and it has never been enough. If you are using 100% real British potatoes, I recommend 100% real British malt vinegar. Otherwise, you can use whatever vinegar you want.
Boil the eggs and chop them up.
Mix everything together (white potatoes with vinegar, orange mixture, eggs).
Delicious potato salad
My housemate calls this "Tang potato salad" because it turns out orange.
I think this is the most delicious potato salad because the sweet potatoes make it... sweet. I have to stop myself from eating more than is prudent in one sitting.
By the way: Because I have lots of friends who are vegan or allergic to dairy, I tried modifying this by mixing olive oil with the sweet potatoes and eliminating the sour cream and mayonnaise. Epic fail. It was not at all delicious. I am sure that it is possible to make a vegan potato salad, but that is not how to do it.