Preheat your oven to 350°F (175°C). Lightly grease and flour two 8-inch x 3-inch round cake pans or spray with nonstick cooking spray. (Note: 8-inch cake pans with shorter sides may cause an overflow in your oven; use taller pans if possible.) Set aside.

In the bowl of a large stand mixer, combine the all-purpose flour, granulated sugar, unsweetened cocoa powder, baking soda, baking powder, and kosher salt. Mix on low speed for 30 seconds to combine the dry ingredients evenly.

In a separate medium bowl, whisk together the buttermilk, vegetable oil, large eggs, and pure vanilla extract until well combined and smooth.

With the mixer on low speed, slowly pour the wet ingredients into the dry ingredients. Once partially combined, slowly add the hot coffee. Continue to mix just until the batter is smooth and no dry streaks remain, scraping down the sides and bottom of the bowl with a rubber spatula as needed. The batter will be thin.

Divide the batter evenly between the two prepared cake pans. Bake for 30-40 minutes, or until a wooden skewer or toothpick inserted into the center of the cakes comes out with only moist crumbs attached, but no wet batter.

Allow the cakes to cool in their pans on a wire rack for 30 minutes. After 30 minutes, carefully invert the cakes onto the wire rack to cool completely before attempting to frost.

Once the cakes are completely cool, frost generously with your favorite chocolate buttercream frosting or any desired frosting.