01 - Preheat oven to 350°F. Grease a 9x13-inch baking pan and line with parchment paper.
02 - In a large bowl, whisk together granulated sugar, flour, unsweetened cocoa powder, baking powder, baking soda, and salt.
03 - Add eggs, buttermilk, vegetable oil, and vanilla extract to the bowl. Mix until incorporated.
04 - Pour in hot coffee and stir until the batter is smooth and glossy.
05 - Transfer the cake batter to the prepared pan, spreading it evenly.
06 - In a separate bowl, beat softened cream cheese and butter until creamy. Add eggs, one at a time, mixing thoroughly after each addition.
07 - Sift in powdered sugar and cocoa powder. Add vanilla extract and salt, then beat until the mixture is smooth and fluffy.
08 - Carefully spread the gooey layer over the cake batter, ensuring an even distribution.
09 - Bake for 32 to 38 minutes, until the edges are set but the center remains slightly wobbly. Avoid overbaking to preserve a gooey middle.
10 - Allow to cool completely before slicing. Serve at room temperature or gently warmed.