Preheat the oven to 350°F. Spray two 6-inch cake pans with baking nonstick spray. Line the bottom of the pan with 6-inch parchment paper and spray again.
In a large bowl, sift the flour and cocoa powder. Add the sugar, baking powder, baking soda, and salt. Set aside.
1 cup All-purpose flour, ½ cup Unsweetened cocoa powder, ¾ cup White granulated sugar, 1 teaspoon Baking powder, ¼ teaspoon Baking soda, ½ teaspoon Salt
Heat the water in a saucepan until it is steaming. In a medium bowl, mix the oil, vanilla, eggs, and buttermilk. Slowly add in the hot water. Pour the wet ingredients into the dry ingredients and mix until just combined.
⅓ cup Oil, 1 teaspoon Pure vanilla extract, 2 Large eggs, ½ cup Buttermilk, ½ cup Hot water
Pour the cake batter into the cake pans. Bake for 18-20 minutes until a toothpick inserted comes out clean.
Let the cake sit in the hot pans for 10 minutes before transferring to a cooling rack. Cool completely.