Preheat oven to 350ºF. Grease 26 to 28 cup cake tray (2-1/2 inch) or line with paper liners.
Combine water and cocoa powder in a small saucepan over medium-low heat. Stir until smooth and bring to a boil. Remove from heat and stir in chocolate chips until melted. Set aside to cool.
Whisk together flour, sugar, baking powder and salt in a large mixer bowl. Add buttermilk, oil, eggs and vanilla, mix for 1 to 2 minutes on medium speed or until smooth. Add cooked melted chocolate mixture and continue mixing for 1 minute or until well blended.
Portion batter evenly into baking cups, filling each approximately two-thirds full. Bake for 18 to 20 minutes or until a wooden pick inserted in the center comes out clean. Remove from oven. Remove cupcakes from pans and allow to cool completely on wire racks before frosting.
For frosting: Beat butter, corn syrup, vanilla and salt in a large mixing bowl until light and creamy. Gradually add powdered sugar and 1/3 cup milk until fluffy, adding additional milk as needed to reach desired spreading consistency, add drops of blue food colouring. Pipe frosting generously onto cupcakes with a pastry bag and decorative tip. Using sugar sheet cut into 1 inch strip. To create the collar simply fold in the left and right corners to overlap. To make the tie, cut out a tie shape from the pink and yellow sugar sheets and decorate with dots using writing icing.