Preheat the oven to 350℉. Place cupcake liners in a 12 cup cupcake pan. Set aside.
In a medium bowl, sift the flour, cocoa powder, cornstarch, baking powder, baking soda, salt, and sugar together. Set aside.
1 cup All-purpose flour, 1 TBSP Cornstarch, 1/2 cup Unsweetened cocoa powder, 1 tsp Baking powder, 1/4 tsp Baking soda, 1/2 tsp Salt, 1 cup White granulated sugar
Start the water on the stove until steaming. In a large bowl, add the oil, vanilla, eggs, buttermilk, and sour cream and whisk together.
1/2 cup Oil, 1 tsp Pure vanilla extract, 2 Large eggs, 1/2 cup Buttermilk, 1/4 cup Sour cream, 1/2 cup Hot water
Add in the dry ingredients and whisk until combined, but a little lumpy still. Slowly add in the hot water and whisk until combined. This is a runnier batter.
Use a large cookie scoop and spoon the batter into the cupcake liner about 3/4th full.
Bake for 16-18 minutes until a toothpick inserted comes out clean.
Let the hot cupcakes sit in the pan for 10 minutes before transferring to a cooling rack. Cool completely before decorating.