The beauty of mashed potatoes is in making them the day before and reheating.
I like to keep the pan of drained, cooked potatoes in the refrigerator until ready to reheat, mash and serve. The cooling of the cooked potatoes makes fluffier mashed potatoes. The starch molecules tend to explode when reheated, making a fluffier mashed potato. This way, they can be mostly made the day before. I have discovered the hard way that potatoes other than Russets or Yukon Gold tend to whip into a gloppy paste of unappetizing goo. Get out that potato masher for best results or beat minimally with a hand mixer on very low speed.
1Â½ teaspoons salt
1 cup whole milk or in combination with cream or half and half
Â¼ to 1/3 cup unsalted butter
White pepper and additional salt, if desired