3 1/2 lb potatoes (russet, yukon gold) peeled and diced
water to cover
1 1/2 cups heavy cream
4 Tbsp butter
1 1/4 cup sour cream
2 1/2 Tbsp white horseradish drained and squeezed dry
1 tsp dijon
3/4 tsp salt
1/2 tsp ground pepper
Garnish 2 Tbsp chives finely chopped
Place potatoes in a large saucepan with water to cover. Bring water to a boil over high heat. Lower the heat to medium and simmer the potatoes until they are soft about 15-20 minutes. Drain potatoes and transfer them to the electric mixer bowl.
In a small saucepan on low heat, warm the heavy cream with the butter until the butter is melted and cream is hot. Remove from heat.
Beat the potatoes with the paddle attachment on low till they are crumbled. With the mixer on medium, slowly add the warmed heavy cream and butter, the sour cream, mustard, horseradish, and salt/pepper.
Tranfer to a double boiler set over simmering water. The should stay warm for 30 minutes.