Instructions

• Preheat the oven to 350°F (175°C). Spray a 9×13-inch baking dish with nonstick cooking spray and set aside.
• Prepare the fudge brownie batter according to the Fudge Brownies Recipe, omitting any nuts called for in that recipe.
• Break 4 Mint Oreos into large pieces and fold them evenly into the prepared brownie batter.
• Pour the brownie batter into the prepared 9×13 pan and smooth the top. Arrange the remaining 12 Mint Oreos evenly on top of the batter.
• Bake the brownies 45–50 minutes, until the center no longer moves when you gently shake the pan or a toothpick inserted in the center comes out with moist crumbs but no wet batter.
• Remove the pan from the oven and let the brownies cool in the pan for 20–30 minutes.
• While the brownies are baking, make the espresso buttercream: place the 1/4 cup (21 g) unsweetened cocoa powder in a large bowl or the bowl of a stand mixer and whisk to remove lumps.
• Melt the 1/4 cup (57 g) butter and pour it into the bowl with the cocoa powder. Whisk until smooth and fully combined.
• Add the confectioners' sugar and milk to the cocoa-butter mixture in alternating small portions, using the amounts on the ingredient list: start with 1 cup (113.5 g) confectioners’ sugar, then add 1 tablespoon of the 3 tablespoons (42 g) milk and beat on high for about 1 minute. Continue adding the remaining confectioners’ sugar (up to a total of 1–1 1/2 cups / 113.5–170 g) in increments and the remaining milk (total 3 tablespoons) in 1-tablespoon increments, beating after each addition, until the frosting reaches a spreadable but firm consistency.
• Add the 1/2 teaspoon (2 g) vanilla extract and the 1/4 teaspoon (0.6 g) espresso powder to the frosting and beat briefly to combine until smooth.
• Once the brownies have cooled 20–30 minutes in the pan and are warm but not hot, spread the espresso buttercream evenly over the top.
• Cut the brownies while still warm or after they come to room temperature and serve. Store any leftovers in an airtight container for up to one week.