I'm powerless to resist the lure of any dessert combining peanut butter and chocolate. It's simple, it's classic, and in my opinion, it's the best! :) Under normal circumstances, I probably would have run into the kitchen and started work on this cake the minute I'd seen it. I didn't though because I knew it would spell big trouble. I'd come across it in the week leading up to Shane's marathon, and for that one week he really tries to eliminate all desserts from his diet. Not only would it have been pretty heartless to make this cake featuring one of his favorite flavor combos when he couldn't actually have any, but, perhaps even more importantly, it would mean I'd be left to my own devices with the cake until I could find someone to share it with. And that would be an epically bad idea, assuming I still wanted to fit into any of my clothes this summer. This one would just have to wait.
Luckily, not for long. As soon as the race was over, this was one of the first things I got to work on. It was the perfect celebratory treat! Though there are three components to the cake, it's really not a ton of work. The base is a fluffy chocolate cake that can be whipped up in about 10 minutes with just a bowl and a whisk. Once it's baked, you slice it in half horizontally and fill it with a creamy peanut butter mixture. It's a bit of an unusual filling in that it's not a fluffy frosting - it's more fudgy in texture. Still delicious, just different. (If you'd rather have a more traditional frosting on the inside, this peanut butter icing is my favorite and would be great here.) The topping is a simple ganache that sets on the cake to an almost fudge-like consistency as well. I couldn't help but garnish the cake with chopped peanut butter cups, but salted peanuts would be a good option too. As you've probably gathered by now, this is a really decadent cake. Cut small slices, and grab a glass of milk on the side. You're going to need it!
Fudge-Glazed Creamy Peanut Butter Chocolate Cake
adapted from King Arthur Flour
1 cup (7 oz) sugar
1 cup (4 1/4 oz) all-purpose flour
1 tablespoon (1/4 oz) cornstarch
1/3 cup (1 oz) Dutch-process cocoa powder
1 teaspoon baking powder
1 teaspoon instant espresso powder
1/4 teaspoon baking soda
1/2 teaspoon salt
2 large eggs, at room temperature
1/3 cup canola oil
1 teaspoon vanilla extract
1/2 cup + 2 tablespoons room temperature water
3/4 cup (7 oz) creamy peanut butter
2 cups (8 oz) confectioners' sugar
1 teaspoon vanilla extract
1/3 cup heavy cream
1 cup (6 oz) semisweet chocolate, finely chopped
6 tablespoons (3 oz) heavy cream
chopped peanut butter cups, for garnish (optional)
Preheat oven to 350 F. Spray an 8-inch cake pan (with at least 2-inch sides) with nonstick cooking spray with flour.
To make the cake: In a large bowl, whisk together the sugar, flour, cornstarch, cocoa powder, baking powder, espresso powder, baking soda and salt. Add the eggs, canola oil and vanilla and whisk to combine. The mixture will be very thick - just make it as uniform as you can. Add the water, a little at a time, whisking in between each addition. Continue until you've added all of the water - the batter should be smooth and fairly thin.
Transfer the batter to the prepared pan. Bake for 35-37 minutes, or until a toothpick inserted in the center comes out clean and the cake springs back when gently pressed with your fingertip. Transfer the pan to a wire rack and cool for 15 minutes, then turn the cake out onto the rack to cool completely.
To make the filling: In the bowl of a stand mixer fitted with the paddle attachment, beat the peanut butter, sugar and vanilla together until the mixture resembles coarse crumbs. Add the cream, beating until the filling is smooth - it will be somewhat thick, but still spreadable. You can add additional cream to adjust the consistency, if necessary.
To make the glaze: Combine the chocolate and cream in a microwave-safe bowl, and heat for 30 seconds on 50% power. Gently stir, then continue heating in 20-second intervals on 50% power, stirring in between each, until the chocolate is completely melted and the glaze is smooth. Set aside for 30-45 minutes, or until the mixture thickens enough to be spreadable.
To assemble: Use a long, thin knife to cut the cake in half horizontally to make two layers. Place the bottom, cut side up, on a serving plate. Spread with the peanut butter filling, then lay the second half of the cake on top, cut side down. Spread the glaze over the top and sides of the cake. Garnish with chopped peanut butter cups. (The cake will slice much more neatly if you dip the knife in hot water first. Wipe on a clean towel before cutting.)