Preheat oven to 350°F. Line a 12 cup muffin tin with muffin liners.
In a large bowl, sift the flour, cocoa powder, baking powder, and baking soda. Add in the sugar, brown sugar, and salt. Whisk until combined.
In a separate bowl, mix the oil, vanilla, eggs, and buttermilk. Slowly add the wet ingredients into the dry ingredients. Mix until combined. Scrape the bowl.
Heat the water in a sauce pan until hot and steaming. Pour the hot water into the batter a little at a time. Whisk until combined and add in more hot water.
Use a cookie scoop to fill the muffin liners ¾ full. Bake for 18-20 minutes. Cupcakes are done baking when a toothpick inserted comes out clean.
Let the cupcakes sit in the pan for 10 minutes. Then, transfer to a cooling rack. Allow the cupcakes to cool completely.