These mashed potatoes are slightly tangy because they contain yogurt. Etc.

Here is a similar, simpler recipe using buttermilk.

1. In a large pot of boiling salted water, cook the potatoes for about 15 to 20 minutes or until fork-tender. Drain.

2. Mash the potaoes somewhat in the pan with a potato masher. Add the salt, pepper, and chives and blend well into the potatoes with the masher while adding room temperature buttermilk to get the desired consistency. Taste for seasoning. Transfer to a serving bowl and serve immediately, or cover with plastic wrap and reheat im a microwave oven just before serving. If it is to be served soon the bowl can be warpped in towels to keep it warm, or even kept warm over hot water.

Ron in Minnesota who has served this to people who hate buttermilk or sour cream or yougurt, and they never notice.