Put the potatoes into a large pot, add the bay leaf, 2 tablespoons salt, and cover with cold water. Bring to a boil over medium-high heat and cook until the potatoes are tender, about 20 minutes. Drain them well and remove the bay leaf. Meanwhile, heat the cream and butter in a small saucepan. Put the potatoes through a ricer or food mill into a bowl. Add the hot cream and season with salt and pepper. Mix together with a spoon and add the chives.