2) Put them into a medium-sized pot and add the garlic, bay leaves, salt and pepper, to taste. Cover with the cream and milk and set over medium-high heat. Bring to a boil then reduce the heat to a simmer and cook until the potatoes are very tender, about 30 minutes.
3) When cooked, discard the bay leaves and the drain potatoes, reserving the cooking liquid. Mash the potatoes with a potato masher using 350ml of the cooking liquid; use more if necessary. Alternately, run the potatoes through a ricer or a food mill over a bowl and ladle in some of the cream mixture so they become creamy.
4) Stir in the horseradish and chopped chives and season with salt and pepper, to taste. Transfer to a serving bowl and serve immediately.