Red Velvet Brownies

Brownies - Adjust oven rack to middle position and preheat to 350ºF (175ºC). Line an 8- by 8-inch baking pan with parchment paper.

Brownies - In a medium microwave-safe bowl, combine butter and chocolate, and microwave on medium power until melted and smooth, stirring every 30 seconds, about 2 minutes.

Brownies - Add granulated sugar and brown sugar to butter-chocolate mixture, and whisk until just combined. Whisk in eggs, vanilla, and food coloring (if using) until smooth. Add flour, cocoa powder, and salt; using a flexible spatula, fold dry ingredients into chocolate mixture until smooth and no streaks of flour remain. Add vinegar, and fold until incorporated. (If you plan to serve the brownies without the frosting, whisk the eggs and sugar together in a separate bowl before incorporating it into chocolate and butter mixture, which will ensure your top is shiny and crackly.)

Brownies - Transfer batter to prepared baking pan and bake until top is crackly and a toothpick inserted into the center has some moist crumbs attached, 28 to 32 minutes. Remove from oven and let brownies cool completely in pan on a wire rack, about 2 hours.

Cream Cheese Frosting - In a large bowl, combine cream cheese and butter and, using an electric hand mixer, beat on low speed until smooth and fluffy, about 1 minute. Add vanilla and salt, and beat until fully combined, about 10 seconds. Add confectioners' sugar, 1/4 cup at a time, beating after each addition until incorporated. Increase speed to medium and beat until fluffy and smooth, about 20 seconds. (Alternatively, frosting can be prepared in the bowl of a stand mixer fitted with the paddle attachment.)

Cream Cheese Frosting - Using an offset spatula or flexible spatula, spread frosting evenly across cooled brownies. Refrigerate until frosting is set, about 15 minutes.