Heaven and Earth (Hemel en Aarde)

Heat oven to 400°F.

Beat butter into potatoes; stir in remaining ingredients. Spoon into 1-1/2 quart casserole, lifting peaks with back of spoon. Bake until hot, about 30 minutes. Increase heat to 550°F and/or broil. Broil until surface brown slightly, about 3 minutes.