- Put potatoes in a large saucepan; add cold water to cover and ½ teaspoon salt. Bring to a boil, reduce heat to medium and continue to cook until potatoes are tender when pierced with a knife – 15 to 20 minutes.
- Meanwhile, heat half-and-half and butter in a small saucepan and bring just to a simmer.
- Drain potatoes and let cool slightly. Rice potatoes into pan or, if using a hand masher, mash potatoes until completely smooth.
- Using a wooden spoon, stir in half-and-half mixture, horseradish, remaining ¼ teaspoon salt and pepper to taste. Serve immediately.