Peel potatoes and cut into 1-inch cubes. Wash thoroughly, and place in a large saucepan. Cover with cold water.
Place over medium-high heat, uncovered, and bring to a full boil. Using a spoon, skim off the foam that collects on top of the water. Reduce heat and keep potatoes boiling.
When half of the water has evaporated and potatoes are very soft, add butter, salt, and pepper. Continue to cook until most of the moisture has evaporated and the remaining liquid has thickened from the starch of the potatoes. (Don't let the potatoes burn on the bottom!)
Taste and add more salt and pepper if needed. Stir and serve. Makes 4-6 servings. Enjoy!