Preheat your oven to 350ºF and line a cupcake tray with 6 liners.
Mix together the flour, cornstarch, cocoa powder, baking soda and salt in a bowl.
In a separate bowl, mix together the sugar and oil until combined, then beat in the egg, food coloring, vanilla, syrup, and lemon/lime juice.
Add the flour mixture to the wet ingredients alternately with the buttermilk, starting with the flour, then the milk, until all has been added. mix until combined.
Fill the cupcake liners about ¾ full, with just a bit of space at the top.
Bake cupcakes for 18-20 minutes or until a toothpick comes out clean. cool before frosting!