I believe my heart sunk right into this skillet’s fudgy middle even before it was cool enough to cut a square. These are brownies that satisfy like no other; they’re intensely chocolatey, chewy yet still fudgy, and made even more decadent with swirls of gooey caramel sauce and a healthy sprinkle of flaky sea salt.
4 ounces bittersweet chocolate (60 to 70% cacao), finely chopped
8 tablespoons (1/2 cup) unsalted butter, cut into small cubes
3/4 cup granulated sugar
2 large eggs
1 teaspoon vanilla extract
2/3 cup all-purpose flour
1/4 teaspoon fine salt or 1/2 teaspoon kosher salt
2 heaping tablespoons good-quality caramel sauce
1/4 teaspoon flaky sea salt
1. Arrange a rack in the middle of the oven and heat to 350°F. Place the chocolate in a large bowl.
2. Melt the butter in an 8- or 9-inch cast iron skillet over medium heat. Pour the melted butter over the chocolate, leaving a film of butter on the pan. Set the pan aside. Let the mixture sit for a minute, then stir to evenly combine — the chocolate should be melted and the mixture should be smooth.
3. Add the sugar and whisk to combine. Whisk in the eggs, one at a time, followed by the vanilla. Whisk vigorously for about 1 minute. Stir in the flour and salt.
4. Transfer the batter to the skillet and spread into an even layer. Drop dollops of the caramel sauce all over the top. Using a butter knife, gently swirl the caramel sauce into the batter, running the knife lengthwise and crosswise. Sprinkle the top evenly with the flaky sea salt.
5. Bake until a tester inserted in the center comes out with just a few crumbs, 25 to 30 minutes. The edges should look firm and well-baked, the center should be moist but not gooey, and the caramel sauce should be bubbling.
6. Cool completely in the skillet on a wire rack. Cut into squares and serve.