Warm Milk Chocolate Souffles with Vanilla Ice Cream

Position rack in center of oven and preheat to 350 °F. Butter eight 3/4-cup soufflé dishes. Coat soufflé dishes with sugar. Arrange soufflé dishes on heavy large baking sheet. Stir milk chocolate and butter in medium metal bowl set over saucepan of simmering water until chocolate mixture is melted and smooth (do not allow bottom of bowl to touch water). Cool chocolate mixture to lukewarm. Using electric mixer, beat egg yolks, whole eggs, and sugar in large bowl until pale, thick, and tripled in volume, about 6 minutes. Fold 1/3 of egg mixture into lukewarm chocolate mixture to lighten. Gently fold chocolate mixture into remaining egg mixture. Spoon into prepared dishes, dividing equally. Smooth tops. Bake until soufflés rise and edges are crisp and dark brown but centers are still soft, about 25 minutes. Dust tops with powdered sugar. Transfer to plates. Serve immediately, passing ice cream separately.