Chocolate Stout Rosemary Cake

Ingredients

Chocolate Stout Cake

• canola oil spray or canola oil
• 1 3/4 cups all-purpose flour
• 1 3/4 tsp baking soda
• 1/2 cups sour cream
• 2 large eggs
• 1 tbsp vanilla extract
• 3/4 cups irish stout
• 1 3/4 cups unsalted butter
• 1 1/2 cups granulated sugar
• 3/4 cups unsweetened dutch-process cocoa powder

Rosemary Fromage Frais Buttercream

• 1/4 cups rosemary-infused butter
• 2 tbsp unsalted butter
• 1 1/2 cups powdered sugar
• 1 1/3 cups fromage frais or cream cheese
• 1/8 tsp fine sea salt

Rosemary-Infused Butter

• 1 3/4 cups unsalted butter
• 1/4 cups fresh rosemary needles

Instructions

1. Set a rack in the middle of the oven and preheat to 350°F (180°C). Spray or brush the sides of an 8-inch round cake pan with canola oil, then line the bottom with parchment paper.
2. Sift the flour and baking soda into a medium bowl. In another medium bowl, whisk together the sour cream, eggs, and vanilla.
3. In a large saucepan, combine the stout and butter and warm over medium heat until the butter is completely melted. Remove from the heat, then whisk in the granulated sugar and cocoa powder until fully incorporated.
4. Add to the sour cream mixture and whisk until fully incorporated. The batter should be dark in color and very thin. Whisk in the flour mixture just until there are no clumps of flour.
5. Pour the cake batter into the prepared pan, smoothing the top. Bake until the cake springs back when lightly pressed and a skewer inserted in the center comes out clean, 50 minutes to 1 hour.
6. Let the cake cool in the pan on a wire rack for 30 minutes. Carefully run a small offset spatula between the edges of the pan and the cake, then flip the pan onto the rack and tap it to make sure the cake is released. Remove the parchment paper. Use a second rack or a plate to flip the cake so it’s right-side up on the rack. Let cool completely.
7. In a stand mixer fitted with the paddle, beat the rosemary-infused butter and unsalted butter on medium-high speed until lighter in color and slightly voluminous, about 2 minutes.
8. Scrape down the bottom and sides of the bowl, then add half of the powdered sugar and beat on medium-low speed until mostly incorporated. Scrape the bowl again, then add the remaining powdered sugar and beat on medium-low speed until fully incorporated — the mixture will be quite firm.
9. Scrape the bowl, then add the fromage frais in four batches, beating on medium speed and scraping the bowl before each addition, until smooth and uniform. Add the salt and beat on high speed until very fluffy, about 1 minute. The buttercream will be very soft. Cover and refrigerate for at least 1 hour to firm up the buttercream and give it more structure.
10. Place the cake flat-side down on a cake plate or stand. Using a rubber spatula, put a large dollop of the buttercream on top of the cake. Use a small offset spatula to spread the buttercream on top of the cake, then use the tip of the spatula to create some swooshes and texture on top. Dust with cocoa powder, if desired.
11. In a small saucepan, melt the butter over medium-low heat. Remove from the heat, stir in the rosemary, cover, and let stand for 30 minutes. Pour through a fine-mesh sieve set over a medium bowl, pressing on the rosemary to extract as much flavor as possible (discard the rosemary). Cover and refrigerate, stirring every 20 minutes, until the butter starts to firm up, about 1 hour, then leave it alone to chill completely.