Preheat the broiler.
On a foil-lined baking sheet, place half of the marshmallows in a single layer; broil until charred, about 3 minutes. Transfer to a plate to cool. Place the remaining marshmallows on the sheet and roast just until toasted, about 2 minutes. Transfer to a plate and let cool. In a blender, mix the ice cream, milk, sour cream and charred marshmallows. Serve topped with the toasted marshmallows.
This recipe was provided by a chef, restaurant or culinary professional and may have been scaled down from a bulk recipe. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.