In a large 8-quart punch bowl, combine Irish cream liqueur, coffee liqueur, brewed coffee, and heavy cream. Stir gently to blend. Top the punch with a generous layer of whipped cream, piping it into decorative dollops if desired. Lightly dust the whipped cream with cocoa powder for a festive touch. Serve with a ladle, pouring into glasses. Garnish each glass with a layer of whipped cream and a sprinkle of cocoa powder.