Preheat oven to 350°F and line a muffin pan with paper liners
Add cocoa powder and coffee to a large bowl and stir until cocoa powder is fully dissolved.
Add sugar and vegetable oil to cocoa and coffee mixture and stir well.
Using electric mixer, blend in milk and egg, Mix until well blended.
In separate bowl, sift together flour, cornstarch, baking powder, baking soda and salt.
Add dry ingredients to wet and stir to combine.
Beat mixture on low speed for 1 minute, switch to medium speed and continue beating for 4-5 minutes
Fill prepared muffin cups about ⅔ full
Bake in preheated oven for 25 - 30 minutes or until a toothpick inserted in centre of cupcake comes out clean
Remove cupcakes from pan and cool completely on wire racks before decorating
