Makes: One 9 × 13-inch (23 × 33 cm) cake
Cake
2¼ cup all-purpose flour, sifted
1½ tsp baking powder
½ tsp baking soda
½ tsp kosher salt
¾ cup unsweetened Dutch-process cocoa powder
1¾ cup granulated sugar
8 Tbs butter at room temperature
2 bananas, roasted in the peel at 350°F (177°C) until soft, then cooled, peeled, and pureed
12 oz (355 ml) pastry stout
4 large eggs
Preheat the oven to 350°F (177°C). Lightly grease and flour one 9" × 13" (23 × 33 cm) pan. Sift together the flour, baking powder, baking soda, salt, cocoa, and sugar into a large mixing bowl. Add the butter and mix at low speed for 1 minute. With the mixer running, add the pureed banana and mix about 30 seconds more.
Add the beer all at once. Mix for 1 minute at low speed, stop and scrape the sides and bottom of the bowl, then mix for 30 seconds more. Add the eggs one at a time, beating well at medium-high speed after each addition.
Scrape the sides and bottom of the mixing bowl and mix for 30 seconds more. The batter will be thin. Transfer the batter to the prepared pan, smooth out the top with an offset spatula. Bake for 33–36 minutes.
The cake is done when the top springs back when very lightly touched in the center and the edges just begin to pull away from the edge of the pan. A cake tester or toothpick inserted in the center will come out clean.
Remove the cake from the oven and let cool completely in the pan on a rack before removing from the pan to frost.
Frosting
3 oz (89 ml) pastry stout
¼ cup + 2 Tbs Dutch-process cocoa powder
3 sticks of butter, room temperature
½ cup powdered sugar, sifted
½ tsp kosher salt
1 lb (454 g) melted and cooled semisweet chocolate squares (not morsels)
Bring the beer to a simmer and whisk in the cocoa powder until dissolved. In the bowl of a stand mixer, whip the butter, sugar, and salt until fluffy, then add the cooled chocolate. Scrape the sides of the bowl. Add the cooled beer mixture then scrape the sides.
Evenly spread frosting over the cake with a spatula.
Beer Tasting Notes: Dessert (or pastry) stouts are a relatively new phenomenon where brewers take a base stout and get creative, mimicking the flavors of familiar breakfast items and desserts. From German chocolate cake and tiramisu to French toast and horchata, the variations are endless, and current demand shows no sign of slowing. These beers are full of adjunct ingredients (such as peanut flour, cacao nibs, vanilla, coffee), sometimes barrel aged, and generally on the higher ABV side. Brewers tend to build the bodies of these beers to be viscous, intense, and rich, making them great beers for their namesake—dessert!
For the majority of these beers, you’ll get a nice, full, tan head between ½ and 1 inch. The base aromas will be dark chocolate, a bit of roast coffee, with very little floral hop character. Flavors of the intended dessert will generally be intense, heightened by typically high finishing gravities, and may be overwhelming at first. After a few sips, the nuanced and subtle flavors—cinnamon, vanilla, and other spices—will generally emerge. The beer will finish sweet, sometimes with lightly bitter roasted coffee notes, and that sweetness will often linger. While few “classics” exist in this style, beers such as Founders CBS (Canadian Breakfast Stout), Stone w00tstout, and Prairie Bomb! all fall under its umbrella. Try some from your local brewery and determine what you like.
What the Beer Does for the Dish: This is where the fun happens—on its own, this cake is very chocolatey, rich, moist, and decadent, with some caramelized banana creaminess. It makes a great base for a variety of dessert-stout flavor approaches, and it would be quite fun and enjoyable to prepare several versions of the cake using different flavored beers. In general, the beer will add more sweetness and layered decadence than the standard preparation of water and milk. Roasting the bananas adds a touch of caramelization, which can really bring out complementary spices in the stouts. A pastry stout that’s heavier on the spices (Stone Xocoveza and Copper Kettle Mexican Chocolate Stout come to mind) will help balance the sweet, rich notes by pushing those spices to the forefront. The peppers will be present but muted, balanced by the sweetness of the cake itself.
Alternatively, a “traditional” dessert stout evoking tiramisu (such as Surly Tiramisu Funeral Bar) will allow the espresso to become very prominent, matching the roast character and really balancing out the chocolate notes. Or go with the German chocolate cake stout and get those coconut flavors to burst through with the caramelized banana while adding more chocolatey goodness to the cake and frosting. For the height of decadence, choose one pastry stout for the cake and a completely different one for the frosting. Just be prepared to have your mind blown in flavor bliss.