Place cubed cake in bottom of large glass serving bowl. Layer the blueberries, raspberries and blackberries on top of the cake. Sprinkle with praline liqueur. In a medium bowl, combine pudding mix, milk, condensed milk and 1 cup of whipped topping, stir well. Pour mixture over frozen berries. Top custard with remaining cool whip. Let sit at room temperature for 1 hour or in refrigerator for 2 to 3 hours, enough for the berries to thaw before serving.