In a medium saucepan place potato chunks and approximately 1 Tablespoon of salt. Fill with water, covering potatoes and bring to a boil over high heat.
Reduce the heat to medium, cover and cook the potatoes until fork tender (approximately 20 minutes).
Drain potatoes and place potatoes back into the pan, off the heat. Mash the potatoes and add butter by Tablespoon, stirring until melted.
Add goat cheese and cream. Continue blending until creamy and smooth.
Add remaining ingredients (horseradish, Horseradish Mustard, scallions, salt and pepper). Stir until blended.
Serve warm. Garnish with additional scallions, if desired.