in a covered saucepan, cook the potatoes in a water to cover mixed with 1 teaspoon of the salt until they are fork tender, about 20 minutes. remove the pan from the heat, drain the potatoes, and replace the lid, allowing the potatoes to steam for 15 minutes.
2. meanwhile, cook the eggs with the vinegar and the remaining 1 teaspoon salt in water to cover, until just done, about 10 minutes. drain and run cold water over them to cool. peel, slice and dice eggs.
3. peel the potatoes and return them to the cooking pot. add the butter to the pot, cutting through the potatoes with sharp knife to allow 