Bittersweet Chocolate Sour Cream Skillet Cake
8 tablespoons (112 g) unsalted butter + 1 tablespoon (14 g) more
3 ounces 70% cacao bittersweet chocolate, chopped
1 1/2 cups (210 g) all purpose gluten free flour blend (I like Better Batter here)
3/4 teaspoon xanthan gum (omit if your blend already contains it)
1/2 cup (40 g) Dutch-processed cocoa powder
1/2 teaspoon baking powder
1 teaspoon kosher salt
1/4 cup (50 g) granulated sugar
1 cup (218 g) packed light brown sugar
1/4 cup (56 g) sour cream, at room temperature
3 extra-large eggs at room temperature, beaten
1 teaspoon pure vanilla extract
1/2 cup (4 fl. oz.) buttermilk, at room temperature
Confectioners’ sugar and cocoa powder, for dusting
Preheat your oven to 325°F.
Place 8 tablespoons butter and the chopped bittersweet chocolate in a small, microwave-safe bowl. Microwave for 1 minute on 60% power, and stir to melt the chocolate. If all of the chocolate has not melted, microwave once more for 30 seconds on 60% power, and stir until the chocolate is melted and smooth. Set the mixture aside to cool a bit.
In a large bowl, place the flour, xanthan gum, cocoa powder, baking powder, salt, granulated sugar and light brown sugar, and whisk to combine well, working out any lumps in the brown sugar. Add the cooled chocolate and butter mixture, then the sour cream, eggs, vanilla and buttermilk, mixing to combine after each addition. The batter will be thickly pourable.
Place the remaining 1 tablespoon butter and place it in a seasoned 10-inch cast iron skillet, and place the skillet in the preheated oven for about 5 minutes, or until the butter has melted. Remove the skillet from the oven and swirl the butter around to coat the bottom of the pan. Pour the cake batter into the pan, and shake the pan to evenly distribute the batter in an even layer. Place the skillet back in the oven and bake, rotating once during baking, until the cake has begun to pull away from the sides of the pan and a toothpick inserted into the center of the cake comes out mostly clean, about 35 minutes. It is better to underbake the cake than to overbake it.
Remove the cake from the oven and allow it to cool completely. Sift confectioners’ sugar and cocoa powder on top of the cooled cake, to taste. Slice and serve at room temperature.