Preheat oven to 325 degrees F. Line muffin tins with 18 paper liners.

Sift the flour, cocoa powder, baking soda, baking powder, and salt into a medium bowl.

In the bowl of an electric mixer beat the butter and sugar on high speed until combined. Add the eggs, one at a time, until incorporated. Continue beating at medium-high speed until mixture is light and fluffy, about 6 more minutes. On low speed, add a 1/3 of the flour mixture. Beat in buttermilk and vanilla, then another 1/3 of flour mixture. Beat in coffee then remaining flour until combined. Divide batter evenly between muffin tins, filling each cup a little more than halfway. Bake for 25 minutes, or until the centers spring back slightly when pressed. Allow to cool completely on wire racks.

In the bowl of an electric mixer beat the butter and peanut butter until combined. On low speed add the sugar. Increase speed to high and beat for 3-5 minutes, until smooth and light. Spoon the filling into a pastry bag fitted with a medium plain tip. Insert tip into the center of each cooled cupcake and fill with about 1 tablespoon of peanut butter filling.

Place the chocolate in a medium, heat-proof bowl. Heat the cream in a small saucepan until scalding then pour over chocolate. Let sit 1 minute then stir until chocolate is melted and mixture is smooth. Let ganache stand at room temperature for 10 minutes, or until thick but still pourable. Dip each cupcake into ganache then sprinkle with chopped peanuts. Transfer to the refrigerator for 20 minutes to set. Store cupcakes in an airtight container in the refrigerator for up to 3 days.