In a saucepan over low heat, combine sweetened condensed milk and caramel topping, stirring until smooth and blended. Slowly pour the warm topping mixture over the top of the warm cake, letting it sink into the slits; then sprinkle the crushed chocolate toffee bars liberally across the entire cake while still warm. (Hint: I crush my candy bars into small chunks)
Let cake cool completely, then top with whipped topping. Decorate the top of the cake with some more chocolate toffee bar chunks and swirls of caramel topping. Refrigerate and serve right from the pan!