1. Bring to a boil in a large saucepan the potatoes and enough salted cold water to cover. Reduce the heat and simmer until potatoes are tender, approx 10 minutes. Drain well.
2. Combine buttermilk, chipotle, salt & pepper in a 1 cup glass measure stirring until blended. Set aside.
3. Return the potatoes to the saucepan and cook over low heat, stirring constantly, until all the liquid has evaporated. Remove from heat and mash until blended while pouring in the buttermilk.