Step 1

Preheat the oven to 350 degrees Fahrenheit (175°C), and lightly grease a 9x13-inch glass or ceramic pan with non-stick spray or butter.

Step 2

Beat the cake mix, water, vegetable oil, and eggs in a large bowl on medium speed. Then pour the batter into the greased pan.

Step 3

Bake the cake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.

Step 4

Let the cake cool on a wire rack for 5 minutes, then poke holes all over the top using the end of a wooden spoon (don't poke all the way through).

Step 5

While the cake bakes, stir the sweetened condensed milk and 6 ounces of caramel sauce in a saucepan over low heat.

Step 6

When it's smooth, and the cake is ready, carefully pour the caramel evenly over the warm cake. Use a spatula to spread it evenly.

Step 7

Set aside 2 tablespoons of chopped toffee and sprinkle the rest across the cake.

Step 8

Let the cake cool completely, then refrigerate it for at least 2 hours.

Step 9

When it's time to serve, spread the whipped topping evenly over the cooled cake and top it with the remaining toffee and caramel.

Step 10

Serve straight from the pan, and enjoy!