1. Preheat broiler. Place marshmallows on a parchment paper- or aluminum foil-lined baking sheet. Broil 30 seconds or until golden brown. Let cool.
2. Combine milk, ice cream, fudge sauce, and half of marshmallows in a blender; process until smooth and creamy. Pour into glasses. Top with remaining toasted marshmallows, and garnish, if desired.