Give me a chocolate cupcake recipe that takes less than 30 minutes

Ingredients:

- 1 cup all-purpose flour
- 1/2 cup unsweetened cocoa powder
- 1 cup granulated sugar
- 1 tsp baking powder
- 1/2 tsp baking soda
- 1/4 tsp salt
- 1/2 cup milk
- 1/4 cup vegetable oil
- 1 large egg
- 1 tsp vanilla extract
- 1/2 cup boiling water

Instructions:
1. Preheat your oven to 350°F (180°C) and line a muffin tin with cupcake liners.
2. In a large mixing bowl, sift together the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
3. In a separate bowl, whisk together the milk, vegetable oil, egg, and vanilla extract.
4. Gradually add the wet ingredients to the dry ingredients and mix until just combined.
5. Stir in the boiling water until the batter is smooth (it will be thin).
6. Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
7. Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
8. Allow the cupcakes to cool in the tin for 5 minutes, then transfer to a wire rack to cool completely before frosting.

Enjoy your delicious and easy chocolate cupcakes!