Preheat over to 325°
Place metal mixing bowl and mixer whisk(s) into freezer for at least 15 minutes.
Mix together brownie mix, stout beer, butter, and eggs. Pour batter into greased pan (recommend 8 x 8 or 9 x 9 square pan) and place in oven to bake 45-50 minutes. Brownies will be done when a toothpick inserted into center comes out clean.
While brownies bake, prepare the whipped cream. Pour whipping cream, confectioners sugar, cocoa powder, espresso crystals, and Irish Cream into cold metal bowl. Using an electric mixer, whisk whipped cream mixture on medium-high speed for about 5 minutes until stiff peaks form. Whipped cream should be completely solid and stiff when ready.
To make the ganache, combine chocolate and heavy cream in a bowl. Microwave on high for 30 seconds. Stir the heavy cream into the chocolate until mixed. Stick back in the microwave for another 15-30 seconds until melted. Whisk in Irish Stout and Irish Cream and let cool to room temperature.
Allow brownies to cool completely (~ 1 hour) before assembling final product. Spread whipped cream topping over brownies in a ½-in thick layer (alternatively, cut brownies first and then spread whipped cream individually on brownies). Using a spoon, drizzle ganache over brownies. Place in refrigerator until ready to serve.