Preheat oven to 350 °F. Spray a standard muffin pan with baking spray or line with cupcake liners, and set aside. For best results, use a sifter to remove the lumps from the flour and cocoa powder.
In a medium mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, and salt.

Add the oil, vinegar, and vanilla. Pour in the boiling water and stir until the batter is smooth.
Using a large cookie scoop, portion about ¼ cup of the batter into the wells of the prepared cupcake pan, filling each well ⅔ full. Tap the pan on the counter a couple of times to shake out any bubbles.
Bake for 18 to 22 minutes, or until a cake tester comes out clean. Cool the in pan for 15 minutes before turning out onto rack to cool completely.

Serving frost with chocolate buttercream frosting with chocolate shavings or other sprinkles of choice (optional)

You can freeze the unfrosted cupcakes by putting them on a tray until firm, then in a ziplock container. They'll keep for about 3 months.
This recipe is easily halved to make six cupcakes.