Chocolate Ganache Peanut Butter Cupcakes

I made these for my family and they were AMAZING!! The next time I make them, I might make mini cupcakes instead of full sized ones because they are kind of rich, but they're still some of the best cupcakes I've ever had.

Ingredients:
CUPCAKE:
2 cups sugar
1 3/4 cups all-purpose flour
3/4 cup baing cocoa
1/2 teaspoon salt
1/2 teaspoon baking soda
1/2 teaspoon baking powder
1 cup buttermilk
1 cup strong brewed coffee, room temperature (if you're not a big fan of coffee flavored things, like myself, don't let this scare you off, you can barely taste it.)
1/2 cup canola oil
2 eggs
1 teaspoon vanilla extract
FILLING:
1/2 cup creamy peanut butter
3 tablespoons unsalted butter, softened
1 cup confectioners' sugar
2 to 4 tablespoons 2% milk
GANACHE:
2 cups (12 ounces) semisweet chocolate chips
1/2 cup heavy whipping cream
PEANUT BUTTER FROSTING:
1/2 cup butter, softened
1 cup creamy peanut butter
3 tablespoons milk, or as needed
2 cups confectioners' sugar

1. In a large bowl, combine the first six ingredients. Whisk the buttermilk, coffee, oil, eggs and vanilla until blended; add to the dry ingredients until combined. (Batter will be very thing.) Fill paper-lined muffin cups 2/3 full.

2. Bake at 350 degrees for 18-20 minutes or until a toothpick inserted near the center comes out clean. (If you make mini cupcakes, cook those for 10 minutes.) Cool for 10 minutes before removing from pans to wire racks to cool completely.
3. In a small bowl, cream the peanut butter, butter, confectioners' sugar and enough milk to achieve piping consistency. Cut a small hole in the corner of a pastry or plastic bag; insert a small round tip. Fill with peanut butter filling. Insert tip into the top center of each cupcake; pipe about 1 tablespoon filling into each.

4. For the frosting, place chocolate chips in a small bowl. In a small saucepan, bring cream just to a bowl. Pour over chocolate; whisk until smooth. Dip the top of each cupcake into ganache; place on wire racks to set.

5. Place the butter and peanut butter into a medium bowl, a beat with an electric mixer. Gradually mix in sugar, and when it starts to get thick, incorporate milk 1 tablespoon at a time until all of the sugar is mixed in and the frosting is thick and spreadable. Beat for at least 3 minutes for it to get good and fluffy.
6. Place frosting in a pastry or plastic bag with large star tip; pipe onto each cupcake. Top with leftover ganache (if you have any).