Chocolate Peanut Butter Cupcakes (but Better!) - Chocolate Cupcakes with Brownie Base, Chocolate Peanut Butter Mousse, and Peanut Butter Swiss Meringue Buttercream

For me, and likely this is not news to most of you, the worst part of asking someone's opinion is that they actually give it to you. I walk around at any given time with ideas for possible cupcakes bouncing around in my head (sometimes I even remember to write them down), but when you've gone ahead and allowed a friend to make a request, you sort of need to honor it. "Yes, of course, I know you asked for a chocolate-peanut butter cupcake, but wouldn't you rather have this sour-cherry almond one instead?" That's just tacky.

I'm not being fair in this case. Jen didn't actually request this cupcake. I just asked her what kind of flavors she liked. Which really, I should know, since we've been friends for a quarter of a century at this point. We're the kind of friends that go for years without a visit, then pick up right where we left off. I love those friends. In this case, I'm going to be better about seeing her more often since 1.) she lives two hours away from me and 2.) she lives two miles away from my mother, so I haven't any excuses. Plus I have great plans to shove cupcakes in her face for years to come. That's friendship!

So, anyways, Jen and I decided to get together after a long separation, and of course I wanted to bake something for her, so she gave me some options, including citrus and...peanut butter and chocolate. Which is a problem for me. See, I've made a chocolate and peanut butter cupcake and I thought...eh...it's okay. I thought that the filling was too heavy and I don't at all like peanut butter American buttercream. It's too...dry? Cakey? Sweet? I wasn't going to inflict this on Jen - I wanted her to know how important she is to me. Also to impress her a little. Maybe a lot.

So what to do? The cake needed to be rich but not too sweet. Okay, great - there is a marvelous chocolate cake recipe from King Arthur Flour that I absolutely love and adapted for these cupcakes (I've linked to the base recipe because that cake is easy, delicious, and besides which raspberries are in season). I wanted it to have a bottom layer (homemade chocolate wafers! More on that later). The previous "buckeye-style" filling was right out - I wanted a more grown-up filling with the playful feel of chocolate and peanut butter. And there's no better way to gussy up a frosting than to turn it into a Swiss meringue buttercream. It takes the overpowering density of a regular buttercream and makes a silky, classy version of itself. Of course, then I tarted it all up with ganache and mini peanut butter cups, but no one says that you have to.

Good plan, right? Sure! Just give yourself a couple of days if you want to recreate this. Can you make it all in a day? Of course you can. I just know that I would be grumpy if I tried it. Start day one by making the cookie bottoms and the cupcakes, then make the filling and frosting the following day, and you'll be fine (and also won't be sick to death of the chocolate and peanut butter aromas wafting through your kitchen).

Hi Jen! I love you!

Chocolate and Peanut Butter Cupcakes (makes 30) 

(no, I'm not kidding)

Chocolate Cookie (Brownie) Base

This is actually a recipe for chocolate wafer cookies, the kind that you'd use to make a pie crust or an icebox pie. When you bake them in a muffin tin this way the texture becomes more of a fudgy brownie. Any leftover dough can be rolled up and then frozen, so you can slice and bake off your cookies as needed in the future.

1 cup granulated sugar
1/2 cup salted butter
1/4 teaspoon salt
1/2 teaspoon baking powder
1 tablespoon espresso powder
1 extra large egg
2 teaspoons vanilla extract
1 1/2 cups all purpose flour
1/4 cup dark cocoa powder
1/4 cup Dutch-process cocoa powder

In a medium-sized bowl, beat together your sugar, butter, salt, baking powder, and espresso powder.

Beat in the egg and vanilla, the add in the flour and the cocoa. Cover the dough with plastic wrap and chill for at least half an hour.

While the dough is chilling, preheat your oven to 350 degrees and line enough muffin tins with cupcake liners to make 30 cupcakes (I used two 12-count and a 6-count and baked the cupcakes in batches).

Divide the chilled dough into 1-ounce portions and roll into balls. Place one ball into each cupcake liner and smash the dough down flat (you can use your fingers for this, but I found that a squeeze bottle worked really well and made for a faster process). Repeat until all of the cupcake liners have an even layer of cookie dough.

Bake the dough-lined muffin tins for about 10 minutes. You just want the dough to start to firm up; it's going to baked again later. Set aside to cool.

Shall we get going on the batter, now?

Chocolate Cupcakes

1 3/4 cups all purpose flour
2 teaspoons baking soda
1 teaspoon baking powder
1 teaspoon salt
2 cups granulated sugar
1 cup unsweetened cocoa powder (sifted, if necessary)
1/2 cup vegetable oil
1 cup buttermilk
1 cup hot, strong coffee
3 teaspoons vanilla
3 large eggs

Preheat the oven to 325 degrees.

Stir together the flour and other dry ingredients in the bowl of a stand mixer.
 
In a medium bowl, combine the oil, buttermilk, coffee and vanilla. Add to the dry ingredients and beat at medium speed for 30 seconds to 1 minute, or until the batter is smooth.
 
Scrape the sides and bottom of the mixing bowl, then beat in the eggs, one at a time. Continue to mix on medium speed for another minute, or until the batter is smooth.
 
Divide the batter among the prepared muffin tins. Bake for 15-18 minutes, or until a toothpick inserted into the cupcake comes out clean. 

Let the cupcakes cool in the pans for five minutes, then remove to wire racks to cool completely.

Chocolate Peanut Butter Mousse Filling

8 ounces dark to bittersweet chocolate, chopped
2 tablespoons butter
3/4 cup creamy peanut butter (I eyeballed this and so can you!)
4 large egg whites
1 cup sugar
1/4 teaspoon cream of tartar
2 cups heavy whipping cream

Place chocolate and butter in a microwave-safe bowl and heat in 30 second intervals, stirring between each, until melted and smooth.
Place peanut butter in a microwave-safe dish and heat for 15-30 seconds, or until runny. Stir into melted chocolate.
Place egg whites, sugar, and cream of tartar in a heat-safe bowl (I used my metal stand mixer bowl, and check out how silly it looks). Boil two inches of water in a medium saucepan and set the bowl on top. Make sure the bottom of the bowl does not touch the boiling water. Whisk egg white mixture continuously until sugar has dissolved, about 4 minutes. Remove from heat.

Whip egg white mixture on high speed with an electric mixer (I used my stand mixer with the whisk attachment) until glossy and stiff peaks form.

Fold meringue into the melted chocolate/peanut butter. (The mixture will be thick and your arm might get tired from stirring!)
Clean stand mixer bowl and whisk attachment (or use a separate bowl and a hand mixer fitted with the whisk attachment). Add heavy whipping cream to bowl and mix on high speed until stiff peaks form. Fold whipped cream into the meringue mixture.

Continue folding until the filling is smooth and uniform. And now it's time to fill the cupcakes.

To fill the cupcakes, cut out a cone shaped portion out of the top of each cupcake. Cut off the extra cake until just the flat top remains (just like a little hat). Put about a tablespoon (use your common sense and put in enough of the mousse until the cupcake is almost full. Remember that you have to put the hat back on the cupcake). Recently, I've been using a pastry bag fitted with a large round tip to fill the cupcakes. It's quicker and far less messy, but just using a spoon works perfectly well.

Replace the top onto each cupcake and put the cupcakes in the refrigerator to let the mousse set up.

Of COURSE these are overfilled. It's mousse! Plus I'm going to be covering all of that with frosting.

 Since the cupcakes are setting up in the fridge, you can get to work on the buttercream.

Peanut Butter Swiss Meringue Buttercream

5 large egg whites, room temperature
Generous cup of granulated sugar
pinch of salt
1 pound (four sticks) unsalted butter, cut into tablespoons and at room temperature
1 1/2 teaspoons vanilla
1 cup creamy peanut butter

Combine egg whites, sugar, and salt in the heatproof bowl of a standing mixer set over a pan of simmering water. Whisk constantly by hand until mixture is warm to the touch and sugar has dissolved (the mixture should feel completely smooth when rubbed between your fingertips).

Attach the bowl to the mixer fitted with the whisk attachment. Starting on low and gradually increasing to medium-high speed, whisk until stiff (but not dry) peaks form. Continue mixing until the mixture is fluffy and glossy, and completely cool (test by touching the bottom of the bowl), about 10 minutes.

With the mixer on medium-low speed, add the butter a few tablespoons at a time, mixing well after each addition. Once all butter has been added, whisk in vanilla. Switch to the paddle attachment, and continue beating on low speed until smooth, about 2 minutes. Add in the peanut butter (and taste to adjust the flavor - this is your frosting!), then scrape down sides of bowl with a spatula. Continue beating until the frosting is completely smooth.

See how pretty? This was before I added the peanut butter.

To frost the cupcakes, use a pastry bag fitted with a large star tip and just swoop it on. Garnish with chocolate ganache drizzle and mini peanut butter cups (the ones from Trader Joe's are particularly good).

Not sure how to make ganache? It's easy. Also terrifying. Just watch!

Bonus recipe: Chocolate Ganache

7 ounces bittersweet chocolate, chopped
3/4 cup heavy cream

Combine the two ingredients into a microwave-safe bowl. Heat in 30-second increments until the chocolate is mostly melted. Stir gently until the mixture is smooth and glossy and the chocolate is melted completely. Behold the panicked four stages of chocolate ganache made in a microwave:

Oh no.

Oh no oh no come ON

Oh HEY!

Yes!

I used a squeeze bottle to drizzle the ganache over the cupcakes, but you can use a pastry bag or a spoon. Top the cupcakes with a few mini peanut butter cups if you really want to. Done!

Keep these in the refrigerator, covered, but bring to room temperature before serving. Yes, I'm serious. The buttercream is MUCH better if it's not cold enough to come off in one piece.

Now go share with your dearest friend.

Full disclosure: my mother, who is neither a peanut butter nor a chocolate person, tried these and said, "These were really good. I didn't think they would be."