1. Preheat Oven and Prep Pans:2. Preheat oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. Line the bottoms with parchment paper.3. 4. Mix Dry Ingredients:5. In a large bowl (or the bowl of a stand mixer), whisk together the all-purpose flour, granulated sugar, black cocoa powder, baking soda, baking powder, and salt.6. 7. Mix Wet Ingredients:8. In a separate medium bowl, whisk together the buttermilk, vegetable oil, large eggs, and vanilla extract.9. 10. Combine Batter and Add Coffee:11. Pour the wet ingredients into the dry ingredients. Mix on low speed until combined. The batter will be very thick.12. With the mixer on low, slowly stream in the hot coffee. Mix until just combined. The batter will be very thin; this is correct.13. 14. Bake the Layers:15. Pour the thin batter evenly between the prepared pans. Bake for 30-35 minutes, or until a wooden toothpick inserted into the center comes out clean.16. 17. Cool Completely:18. Let the cakes cool in the pans for 15 minutes before inverting them onto a wire rack. Peel off the parchment and let cool completely.19. 20. Make the Oreo Frosting:21. In a large bowl, beat the room-temperature butter and cream cheese on medium-high speed until completely smooth, about 3 minutes.22. 23. Add Sugar:24. Reduce speed to low. Gradually add 4 cups of sifted powdered sugar, mixing until combined. Add the vanilla and salt.25. 26. Beat Until Fluffy:27. Increase speed to medium-high and beat for 2-3 minutes until light and fluffy. If the frosting is too thin, add the remaining 1 cup of sugar.28. 29. Add Oreos:30. Gently fold in the crushed Oreo cookies with a spatula. Do not overmix, or the frosting will turn gray.31. 32. Assemble the Cake:33. Place one cooled cake layer on a serving platter. Top with a generous layer of Oreo frosting.34. Place the second cake layer on top. Apply a thin crumb coat of frosting to the top and sides. Chill for 30 minutes.35. Frost the cake with the remaining frosting. Decorate with more crushed Oreos, if desired.