Malted Cream: Combine the cream and malted milk powder in a small saucepan and heat just until it begins to simmer. Remove from heat and let stand for 20 minutes, then pour the cream through a sieve to make a malt infused cream.
Preheat oven to 350°F. Line an 8 inch square metal pan with nonstick foil.
In a small mixing bowl, beat the cream cheese and sugar until smooth. Beat in the melted chocolate chips and vanilla extract, then stir in the egg, sour cream and 2 tablespoons of the malt infused cream. Chop up the Double Stuff Oreos and add to cream cheese mixture. Set aside.
Make the brownie batter. Melt the butter in a 2 or 3 quart nonstick saucepan. Stir in the sugar and the cocoa powder. Reduce heat to low and stir gently for about 30 seconds to warm the sugar. Turn off the heat and let the sugar mixture sit for 5 minutes. Stir in the salt and vanilla. Add the cold eggs, whisking or stirring just until mixed, then mix the flour and baking powder together in a little cup and stir them into the batter. Spread about half the batter evenly over the bottom of the pan.
Spread the filling over the batter by dropping it on in little dollops and gently spreading. Drop dollops of remaining brownie batter over the filling, spreading gently to cover. It’s okay if you miss a few spots because the top will be covered with frosting.
Pour into the pan and bake for 25 minutes or until brownies appear set. Let cool completely in the pan. When cool, transfer to the refrigerator to chill.
Make frosting. Beat the butter until creamy. Gradually add cocoa powder and confectioners’ sugar, scraping sides and beating until well mixed, but still lumpy. Add a little (about 1 tablespoon) of the malted cream and beat until smooth, then beat in vanilla. Continue adding malted cream mixture 1 tablespoon at a time until vanilla is light and spreadable. Spread over brownies. Chop up the Double Stuff and scatter over top. Chill while making the ganache.
Make the ganache. In a microwave safe bowl or large Pyrex measuring cup, microwave the cream for 30 seconds or just until it starts to boil. Add the chips and stir until the chips are melted and mixture is smooth. Transfer to a heavy duty zipper bag. Cut a tiny hole in the corner of the bag and squeeze lines of ganache over the cold bars. Break up remaining Double Stuff and press them into the top for garnish. Return to the refrigerator to set the ganache. Store in the refrigerator