Turn the oven to 350 degrees F. Combine flour, cocoa powder, sugar, baking soda, and salt into a bowl. Use a fork to completely mix together.
Form three wells in the dry ingredients. Pour oil into one well, vinegar into another well, and water into the third. (The water will most likely run over into the other wells - don't worry!)
Use a fork to stir everything together. Be sure to scrape the bottom of the bowl to get all of the dry ingredients.
Line a miniature cupcake pan with miniature liners. (These are 3/4" liners). Fill each liner 3/4 of the way full, repeat until all liners have been filled.
Pop in the oven, and bake for 10-12 minutes. The tops will be set and firm. Remove from the oven, and allow to cool in the pan for five minutes.
Transfer to a cooling rack for another 10-15 minutes, then frost with desired frosting. Keep in an airtight container for up to two days if not eaten immediately. :)