Preheat oven to 350°F (175°C). Line a muffin tin with cupcake liners.
In a large bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt.
In a separate bowl, whisk together the sugar, oil, eggs, and vanilla extract. Gradually add the dry ingredients to the wet ingredients, alternating with the boiling water, beginning and ending with the dry ingredients. Beat until just combined.
Fill each cupcake liner about 2/3 full.
Bake for 20-25 minutes, or until a wooden skewer inserted into the center comes out clean.
Let cool in the muffin tin for a few minutes before transferring to a wire rack to cool completely. Frost with your favorite frosting.