Mint-and-White-Chocolate Milk Punch

Bring cream, milk, sugar, and vanilla bean to a simmer in a large saucepan over medium heat, stirring often. Remove from heat; add mint sprigs. Cover and let stand 8 minutes. Discard mint and vanilla bean. Add chopped chocolate, and cook over low heat, stirring constantly, 2 minutes or until chocolate is melted. If desired, stir in 2 Tbsp. vodka per 1 cup punch just before serving.