Baked bakers did.
Skillet Chocolate Cake
Copied from Baked Website
1/2 cup unsweetened dark cocoa powder (like Valrhona)
2 ounces good-quality dark chocolate (60 – 72%), coarsely chopped
1 teaspoon instant espresso powder
1 1/2 cups all-purpose flour
1 teaspoon baking soda
1 teaspoon salt
1/2 cup (1 stick) unsalted butter, cut into 1-inch cubes, at room temperature
1 cup firmly packed dark brown sugar
1/4 cup granulated sugar
1 teaspoon pure vanilla extract
3 large eggs
1/4 cup plus 2 Tablespoons buttermilk, shaken vigorously
Make the Chocolate Cake
Preheat the oven to 350 degrees F.
Grease a 10-inch, cast-iron skillet or ovenproof stainless steel skillet with butter. (The heavy, dark-colored cast-iron skillet will makes the sides of the cake more crispy than a stainless steel one.) Line the pan with parchment paper and butter the parchment. Dust the parchment with flour and knock out the excess.
In a small, heatproof bowl, whisk together the cocoa powder, chocolate, and espresso powder. Add 3/4 cup very hot water, wait one minute, and then whisk the mixture until its melted and smooth. Set aside to cool.
In another small bowl, whisk together the flour, baking soda, and salt.
In the bowl of a standing mixer fitted with the paddle attachment, beat the butter and shortening together on medium speed until creamy, 2 to 3 minutes. Add the sugars and vanilla and beat until fluffy, about 3 minutes. Scrape down the bowl, add the eggs one at a time, and beat just until combined. Turn the mixer to the lowest setting, and in a slow, steady stream, add the reserved chocolate mixture. Scrape down the bowl again, then turn the mixer to low. Add the flour mixture in three parts, alternating with the buttermilk, beginning and ending with the flour mixture. Scrape down the bowl, then mix for a few more seconds and pour the batter into the prepared skillet. Smooth the surface with a spatula.
Bake for 40 to 45 minutes, rotating the skillet halfway through the baking time, until a toothpick inserted in the center of the cake comes out clean. Transfer the pan to a wire rack to cool for about 15 minutes. Run a paring knife around the sides of the pan and flip the cake onto a cooling rack. Turn the cake right side up and let it sit on the rack until completely cool.
For the Chocolate Frosting
1/2 cup (1 stick) butter, softened
1 cup confectioners’ sugar, sifted
1 Tablespoon pure vanilla extract
3 ounces good-quality chocolate (60 to 72%), melted and cooled
Make the Chocolate Frosting
In the bowl of a standing mixer fitted with the paddle attachment, beat the butter on high speed until creamy, about 2 minutes. Add the confectioners’ sugar all at once and beat until completely blended, about 2 minutes. Add the vanilla and beat for 15 seconds. Scrape down the bowl and add the melted, cooled chocolate. Beat until smooth, continuing to scrape down the sides of the bowl as needed until the frosting is uniform in color.
Transfer the skillet cake to a cake board or serving platter. Use an offset spatula to spread the frosting evenly across the top. Serve it immediately or refrigerate it, if necessary. Bring it back to room temperature before serving.