Preheat the oven to 400 degrees F (200 degrees C). Place potatoes on a baking sheet and bake for 40 to 50 minutes, until tender enough to easily pierce with a fork. Cool slightly and remove peels.
Place the cooked sweet potatoes into a large bowl and mash with the horseradish, honey, butter and salt. Whip with an electric mixer until light and fluffy, adding heavy cream as needed to get the texture you desire. Serve immediately, or keep warm in the oven until time to serve.