Begin by preheating your oven to 325 degrees Fahrenheit and place cupcake liners in your cupcake pans. (We are baking these at 325 degrees F instead of 350 degrees F because we want the cupcakes to have a nice flat top for decorating, as opposed to a domed top, which you'll get if you bake them at a higher temperature.)
In a large bowl, mix the flour, salt, baking powder, baking soda, cocoa powder, and sugar with an electric mixer at low speed, until just combined.
Next, add the oil, coffee, and milk to the dry ingredients. Mix at medium speed for another 2 minutes.
Now, add the eggs and vanilla extract to the mixture and mix for an additional 2 minutes at medium speed.
Evenly divide the batter between your cupcake liners. (Note, this is a very thin batter.)
If baking standard-sized cupcakes, bake for about 22 minutes until a toothpick stuck into the center comes out done. If making jumbo-sized cupcakes, bake for about 27 minutes, or until a toothpick stuck into the center comes out clean.