Prepare brownies according to the package directions, and let cool. Crumble the surface of the brownies with a fork.
Prepare the chocolate pudding mix according to the package directions, and immediately pour over the brownies. Allow the pudding to set.
Using the handle of a wooden spoon or table knife, crush the toffee bars, still in their wrappers, and sprinkle 7 crushed toffee bars over the pudding.
Spread the whipped topping over the crushed toffee bars with a spatula, and sprinkle 1 crushed toffee bar over the top for decoration.
