Preheat the oven to 350 degrees F. Spray a 9 inch square pan with nonstick spray.
In a medium bowl, whisk together the flour, cocoa, baking powder and salt.
In a large bowl, whisk together the sugar, butter, eggs and extract. Whisk in the dry ingredients and stir until combined. Scrape the batter into the prepared pan.
Bake 35 to 40 minutes, or until the brownies are baked through and a toothpick inserted into the center comes out clean. Let the brownies cool completely in the pan, then cut into 1 inch pieces.
WHIPPED CREAM
In a large bowl, use an electric mixer to whip the cream until it begins to thicken slightly. Add the cream cheese and extract and continue to whip the cream to very soft peaks when you draw the beaters through the cream it will begin to take shape. Don't over beat or it will be too thick.
ASSEMBLY
In a glass trifle dish or tall glass bowl, place a third of the brownie pieces on the bottom and up the sides of the dish. Spoon ⅓ of the whipped cream on top of the brownies, spreading it to the edges.
Break apart 8 Oreos and sprinkle them on top of the whipped cream. Drizzle a few spoonfuls of hot fudge on top. Repeat two more layers.
Garnish the trifle with mint leaves, if desired. Keep refrigerated until ready to serve. Leftovers are perfectly delicious for a couple of days.