Preheat oven to 350F. Butter two 9-inch round cake pans, line bottoms with parchment, and butter the parchment. Whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt in a large bowl until no cocoa lumps remain.

Add buttermilk, oil, eggs, and vanilla to the dry ingredients. Beat with an electric mixer on medium speed for 2 minutes until smooth and thick. The batter will be quite thick at this stage.

Stir in the hot coffee by hand until just combined. The batter will thin out considerably. Divide evenly between prepared pans. Bake 30-35 minutes until a toothpick inserted in the center comes out with a few moist crumbs. Cool in pans 10 minutes, then turn out onto wire racks to cool completely.

Beat peanut butter and softened butter on medium-high speed until light and fluffy, about 3 minutes. Gradually add powdered sugar on low speed, then increase to medium and beat until smooth. Add heavy cream and vanilla, beat 1 minute more until spreadable.

Place chocolate chips in a heatproof bowl. Heat heavy cream until steaming but not boiling, pour over chocolate. Let stand 2 minutes, then stir until glossy and smooth. Cool 10-15 minutes until slightly thickened but still pourable.

Place one cake layer on a serving plate. Spread with about 1 cup of peanut butter frosting. Top with second layer. Frost top and sides with remaining frosting, creating a smooth finish. Chill cake 15 minutes to set the frosting.

Pour ganache over the center of the chilled cake, letting it drip naturally down the sides. Use an offset spatula to gently encourage drips if needed. Let set at room temperature 30 minutes before slicing.