1. Preheat the oven to 350°F and grease two 9-inch round cake pans. Line the bottoms with parchment paper.

2. In a large bowl, whisk together the flour, cocoa powder, granulated sugar, brown sugar, baking powder, baking soda, and salt.

3. In another bowl, whisk the eggs, buttermilk, vegetable oil, and vanilla extract until smooth.

4. Pour the wet ingredients into the dry ingredients and mix until just combined.

5. Slowly stir in the hot coffee or hot water until the batter is smooth and thin.

6. Divide the batter evenly between the prepared cake pans.

7. Bake for 28 to 32 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.

8. Let the cakes cool in the pans for 10 minutes, then transfer them to a wire rack to cool completely.

9. Beat the softened butter and creamy peanut butter together until smooth and fluffy.

10. Add powdered sugar gradually, then mix in heavy cream or milk, vanilla extract, and salt until creamy and spreadable.

11. Place one cake layer on a serving plate and spread peanut butter frosting over the top.

12. Add the second cake layer, then frost the top and sides of the cake.

13. If using ganache, heat the heavy cream until warm, pour it over the chocolate chips, let it sit for 2 minutes, then stir until smooth.

14. Drizzle the ganache over the frosted cake and decorate with chopped peanuts or peanut butter cups.

15. Chill the cake for 20 to 30 minutes before slicing for cleaner pieces.