Preheat the oven to 350°F. Line a 12-cup muffin pan with cupcake liners. Line a second pan with 2 liners - this recipe makes about 14 cupcakes. Set aside.

Whisk the flour, cocoa powder, baking powder, baking soda, and salt together in a large bowl until thoroughly combined. Set aside. In a medium bowl, whisk the eggs, granulated sugar, brown sugar, oil, and vanilla together until completely smooth.

Pour half of the wet ingredients into the dry ingredients. Then half of the buttermilk. Gently whisk for a few seconds. Repeat with the remaining wet ingredients and buttermilk. Stir until combined; do not overmix. The batter will be thin.

Pour or spoon the batter into the liners. Fill only halfway to avoid spilling over the sides or sinking. Bake for 18-21 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting if you want to.