• Preheat the oven to 350°F. Line two cupcake pans with 24 baking cups.
• Place the cocoa powder in the bowl of a stand mixer with the paddle attachment and pour the hot coffee over. Mix on low speed until a thick paste forms and the mixture stops steaming, about 1 minute.
• Increase the mixer speed to medium. In a 4-cup measuring cup, combine the buttermilk, oil, vanilla, egg, egg yolk, and salt and mix lightly with a fork, ensuring yolks are broken. Slowly pour into the mixer bowl.
• Stop the mixer, detach the paddle, and scrape the bottom of the bowl well to loosen any caked-on cocoa. Reattach the paddle and turn the mixer to medium, letting it run for 1 minute. Stop mixer again.
• Sift together the flour, sugar, baking powder, and baking soda and add to the batter. Mix on low speed til just combined. Remove the bowl and paddle and use paddle attachment to scrape down the sides of the bowl, ensuring everything is mixed.
• Scoop the batter into prepared baking cups, filling them two thirds of the way.
• Bake in the middle of the oven for 20 to 25 minutes, rotating the pans halfway through. The cupcakes are done when the centers spring back when you touch them.
• Remove cupcakes from oven. Let cool completely.

Peanut Butter Buttercream

• Pour 1 cup water into a heavy nonreactive saucepan. Add 2 cups granulated sugar, 2 Tbsp. corn syrup, and ¼ tsp. cream of tartar. (The last two prevent the sugar from crystallizing.) Bring to a boil over high heat; continue to cook (you can swirl the pan occasionally, but do not stir!) until sugar dissolves and mixture reaches 230°F, a.k.a. “soft ball stage.” (Be patient and keep your eye on it. Don’t go walking away and watching TV or something.)
• Meanwhile, combine 1 large egg plus 5 large egg yolks in the bowl of a stand mixer with the whisk attachment and turn mixer to high speed. Yolk mixture will triple in volume, turn pale yellow, and go to “ribbon stage.” (You can’t overwhip!)
• When the sugar is ready, move quickly: Turn off the mixer and add ⅛ tsp. xanthan gum, turn back up to medium-low speed.
• Remove thermometer from (very hot!) sugar mixture. Lift with two hands. Rest the lip of the saucepan on the edge of the mixer bowl. With the mixer running, pour the hot sugar syrup in a slow, steady stream down the side of the bowl into the egg mixture. (Don’t go too fast, which may result in chunks of scrambled eggs in your buttercream.)
• Once sugar syrup is incorporated, turn the mixer to high speed and whip until cool. (Gauge this by putting the inside of your wrist to the outside bottom of the bowl. It’s more accurate than your hands.)
• Switch out the whisk for the paddle attachment. Cut 6 sticks (1½ lb.) unsalted butter, cold, preferably European, into thin pieces (you could shave it with a cheese slicer if you’d like). Add butter to the egg yolk mixture piece by piece to make an emulsion.
• Once butter is added, add the peanut butter and salt and mix on high to combine. Taste for seasoning. If desired, add more peanut butter, 1 tablespoon at a time, or a pinch more salt. Continue until, after tasting, your eyes roll into the back of your head.

Chocolate Peanut Butter Pretzels

• Melt the chocolate using a double-boiler method or in a microwave (see notes for description).
• In a medium bowl, add peanut butter, powdered sugar, soft butter, and vanilla. Stir until combined. You want the mixture to be thick but spreadable. I used natural peanut butter which is rather runny. You can adjust the consistency of the peanut butter mixture by adding more sugar if it’s too runny, you can also put it in a fridge or freezer to thicken. You can add more sugar if you want it sweeter.
• Using a knife spread some peanut butter mixture on one pretzel, then top with a second pretzel. Place on a tray lined with parchment paper.
• Dip each pretzel ‘sandwich’ in melted chocolate. You can hold the pretzels by hand if you want to dip just half of a pretzel. If you want to dip whole pretzels (like on the photos), use a fork and tap it against the edge of your bowl to remove the excess chocolate.
• Place the pretzels on a tray lined with parchment paper and sprinkle with flaky sea salt while the chocolate is still wet. Place the tray in the fridge until the chocolate is set (it will take 30-60 minutes).

Assembly

• Fill a pastry bag fitted with a plain tip with the peanut buttercream, and pipe onto each chocolate cupcake. Put the cupcakes into the refrigerator so the buttercream hardens, about 20 minutes.
• Pulse the pretzels and peanuts in a food processor until they're coarse crumbs. Alternately, place in a strong zip-top bag and repeatedly smack the bag with a rolling pin, a heavy skillet, or anything else you find enjoyable. Place the crumbs in a pie dish or baking pan.
• Remove the cupcakes from the refrigerator and gently roll the sides of the buttercream in the pretzel mixture. Pour a handful of the mixture over the top of each cupcake and lightly pack on with hand. Shake off any excess and set aside.
• Top with a Chocolate Peanut Butter Pretzel