Brownies with Salted Caramel Sauce

PreparationFor brownies: Preheat oven to 350°F. Coat an 8x8x2" baking pan with nonstick spray. Dust with cocoa powder, tapping out excess. Place butter, unsweetened chocolate, and bittersweet chocolate in a medium microwave-safe bowl. Heat in microwave in 15-second intervals, stirring occasionally, until melted. Let cool slightly. Meanwhile, whisk flour, espresso powder, kosher salt, and 1 tablespoon cocoa powder in another medium bowl; set aside. Using an electric mixer on high speed, beat eggs and sugar in a large bowl until pale and thick, about 2 minutes; beat in vanilla. Fold in warm chocolate mixture, then dry ingredients, just until combined. Fold in chocolate chips. Scrape batter into prepared pan and smooth top. Bake brownies until a tester inserted into the center comes out with some moist crumbs attached, 20-25 minutes. Transfer pan to a wire rack; let brownies cool in pan. Cut brownies into 16 squares. For caramel sauce and assembly: Bring sugar and 2 tablespoons water to a boil in a small saucepan over medium heat, stirring until sugar dissolves. Increase heat to mediumhigh and cook without stirring, occasionally swirling pan and brushing down sides of pan with a wet pastry brush, until sugar is a deep amber color, 5-8 minutes. Remove caramel from heat. Add cream and butter (mixture will bubble vigorously) and whisk to combine. Let cool slightly in pan. Drizzle caramel sauce over brownies and sprinkle with sea salt. DO AHEAD: Brownies can be made 1 day ahead. Cover and keep at room temperature. Caramel sauce can be made 1 week ahead. Let cool. Cover and chill. Reheat before using.

PreparationFor brownies: Preheat oven to 350°F. Coat an 8x8x2" baking pan with nonstick spray. Dust with cocoa powder, tapping out excess. Place butter, unsweetened chocolate, and bittersweet chocolate in a medium microwave-safe bowl. Heat in microwave in 15-second intervals, stirring occasionally, until melted. Let cool slightly. Meanwhile, whisk flour, espresso powder, kosher salt, and 1 tablespoon cocoa powder in another medium bowl; set aside. Using an electric mixer on high speed, beat eggs and sugar in a large bowl until pale and thick, about 2 minutes; beat in vanilla. Fold in warm chocolate mixture, then dry ingredients, just until combined. Fold in chocolate chips. Scrape batter into prepared pan and smooth top. Bake brownies until a tester inserted into the center comes out with some moist crumbs attached, 20-25 minutes. Transfer pan to a wire rack; let brownies cool in pan. Cut brownies into 16 squares. For caramel sauce and assembly: Bring sugar and 2 tablespoons water to a boil in a small saucepan over medium heat, stirring until sugar dissolves. Increase heat to mediumhigh and cook without stirring, occasionally swirling pan and brushing down sides of pan with a wet pastry brush, until sugar is a deep amber color, 5-8 minutes. Remove caramel from heat. Add cream and butter (mixture will bubble vigorously) and whisk to combine. Let cool slightly in pan. Drizzle caramel sauce over brownies and sprinkle with sea salt. DO AHEAD: Brownies can be made 1 day ahead. Cover and keep at room temperature. Caramel sauce can be made 1 week ahead. Let cool. Cover and chill. Reheat before using.