Preheat oven to 350°. Place cauliflower in a stockpot; add water to cover. Bring to a boil. Reduce heat; simmer, uncovered, 10-12 minutes or until very tender. Drain; transfer to a large bowl. Mash cauliflower; stir in cheeses, cubed butter and seasonings. Transfer to a greased 13x9-in. baking dish.
In a small bowl, mix bread crumbs and melted butter until evenly coated; sprinkle over cauliflower mixture. Bake, uncovered, 40-50 minutes or until heated through and topping is golden brown. Yield: 12 servings (3/4 cup).