Make the Brownies: Adjust oven rack to lowest position and heat oven to 350 degrees F. Line a 9x13-inch baking pan with foil, leaving about a one-inch overhang on all sides. Spray with nonstick cooking spray.
Whisk cocoa, espresso powder, and boiling water together in large bowl until smooth. Add unsweetened chocolate and whisk until chocolate is melted. Whisk in melted butter and oil. (Mixture may look curdled.) Add eggs, yolks, and vanilla and continue to whisk until smooth and homogeneous. Whisk in sugar until fully incorporated. Add flour and salt and mix with rubber spatula until combined. Fold in bittersweet chocolate pieces.
Scrape batter into prepared pan and bake until toothpick inserted halfway between edge and center comes out with just a few moist crumbs attached, 30 to 35 minutes. Transfer pan to wire rack to cool completely.
Make the Creme de Menthe Filling: Using an electric mixer, beat the butter and cream cheese on medium speed until smooth and fluffy, about 2 minutes. Reduce the mixer speed to low and add the creme de menthe and pinch of salt, blending until totally combined. Keeping the mixer on low speed, gradually add the powdered sugar. Once it has all been incorporated, increase the speed to medium and beat until smooth and fluffy. Spread the mixture over the cooled brownies into an even layer. Transfer to refrigerator and chill for at least 30 minutes.
Make the Creme de Cacao Ganache: Place the chocolate, heavy cream and butter in a medium bowl set above a small saucepan of barely simmering water. Cook, stirring constantly, until the mixture is completely melted and smooth. Remove the bowl from the saucepan and stir in the creme de cacao. Set aside to cool to room temperature (the mixture will thicken as it cools), then use an offset spatula to spread in an even layer over the creme de menthe filling. Return to the refrigerator for at least 30 minutes.
Using foil overhang, carefully lift brownies from pan. Cut into squares and serve. Brownies can be stored in an airtight container at room temperature for up to 5 days.