Guinness Brownies

In a small saucepan, bring Guinness to a boil over medium-high heat. Reduce heat to medium-low, and simmer, stirring occasionally, until reduced to 1 cup, about 35 minutes. Remove from heat, and let cool for 30 minutes.

Preheat oven to 350°F (180°C). Spray a 13×9-inch baking pan with cooking spray; line pan with parchment paper, letting excess extend over sides of pan.

In the top of a double boiler, combine chocolate and espresso powder. Cook over simmering water, stirring occasionally, until chocolate is melted and mixture is smooth.

In a large bowl, whisk together granulated sugar, melted butter, brown sugar, eggs, egg yolk, and vanilla until well combined. Add chocolate mixture and ¾ cup (160 grams) reduced Guinness, whisking until well combined. (Reserve remaining reduced Guinness for Malted Frosting.)

In a medium bowl, whisk together flour and salt. Gradually add flour mixture to sugar mixture, whisking until well combined. Spoon batter into prepared pan; using a small offset spatula, smooth into an even layer.

Bake until a wooden pick inserted in center comes out with a few moist crumbs, about 35 minutes. Let cool completely in pan on a wire rack.

Using excess parchment as handles, remove from pan. Spoon and spread Malted Frosting onto cooled brownies as desired. Garnish with chocolate shavings, if desired, and cut into bars.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and salt at medium speed until smooth and creamy, 1 to 2 minutes, stopping to scrape sides of bowl. With mixer on low speed, gradually add confectioners’ sugar, milk powder, and espresso powder, beating just until combined. Beat in reduced Guinness and vanilla; scrape sides of bowl. Increase mixer speed to medium, and beat until fluffy, about 2 minutes, stopping to scrape sides of bowl. Use immediately.