Set up your barbecue for indirect cooking. Please refer to your handbook for further instructions. Preheat your barbecue for baking.
Prepare the cake mixture according to the packet instructions.
Using a 12 cup muffin tray, place an ice cream cone in each cup and ⅔ fill with the cake mixture.
Once the barbecue has preheated, make adjustments to the burner control(s) if required. Place the cupcakes in and cook for 20 minutes.
Once finished baking, remove the cupcakes from the barbecue and place the cupcakes on a cooling rack. Place the remaining cones in the muffin tray, fill ⅔ full with cake mixture and bake for 20 minutes.
While the cupcakes are cooling, make the frosting. Place the icing sugar and butter in a large mixing bowl. Using electric beaters, beat on low for 2 minutes. Continue beating and add the vanilla and 2 tablespoons of the milk. If the frosting is not yet smooth add a little more milk until desired consistency is reached.
Fill a piping bag with the frosting and pipe onto the cooled cupcakes.
Have fun decorating the cupcakes with the sprinkles and chocolate.