Instructions

• Preheat oven to 350°F (175°C). Spray a 9×13-inch baking dish with nonstick cooking spray and set aside.
• Prepare the fudge brownies batter according to the Fudge Brownies recipe, omitting any nuts called for in that recipe.
• Break 4 Mint Oreos into large pieces and gently fold them into the prepared brownie batter.
• Pour the batter into the prepared 9×13 pan and smooth the top. Arrange the remaining 12 Mint Oreos (whole) on top of the batter in a single layer.
• Bake the brownies 45–50 minutes, or until the center no longer jiggles when the pan is moved and a toothpick inserted in the center comes out with some moist crumbs but no liquid batter.
• While the brownies are baking, make the espresso buttercream: place the 1/4 cup (21 g) unsweetened cocoa powder in a large bowl and whisk to remove lumps.
• Melt the 1/4 cup (57 g) butter and pour it into the cocoa powder. Whisk until well combined and smooth.
• Add the confectioners’ sugar and milk in increments, using the amounts listed: start with 1 cup (113.5 g) confectioners’ sugar and about 1 tablespoon (of the 3 tablespoons / 42 g) milk. Beat on medium-high speed (or whisk vigorously) for about 1 minute until combined.
• Add the remaining confectioners’ sugar (the remaining 0 to 1/2 cup / up to 56.5 g to reach the total 1–1.5 cups) and another 1 tablespoon milk. Beat again about 1 minute. If needed, add the final 1 tablespoon milk (up to the total 3 tablespoons) and beat until the frosting is smooth and spreadable.
• Add the 1/2 teaspoon (2 g) vanilla extract and 1/4 teaspoon (0.6 g) espresso powder to the frosting and mix until fully incorporated.
• If the frosting is too dry and you have not used all 3 tablespoons of milk, add additional milk 1 teaspoon at a time (up to the listed total) until it reaches the desired consistency. If the frosting is too thin and you have not used the full 1.5 cups of confectioners’ sugar, add additional confectioners’ sugar 1 tablespoon at a time (up to the listed total) until it holds its form.
• When the brownies are done, remove the pan from the oven and let them cool in the pan for 20–30 minutes so they are warm but not hot.
• Spread the espresso buttercream evenly over the warm (not piping hot) brownies. Let the frosting set for 10–20 minutes, then slice and serve.
• Store any leftovers in an airtight container at room temperature for up to one week.