For the chocolate cake: Follow instructions listed on cake mix box for both cake and frosting.

Notes: I used 2 6" cake pans and extended baking time to 30 minutes.

Make the caramel frosting: In a saucepan over medium heat, melt the butter. Mix in light brown sugar and 2 tablespoons of milk. Whisk to combine and allow to boil for 1 minute. Remove from heat, and mix in ½-cup of powdered sugar and another tablespoon of milk. Whisk to combine. Allow to cool before adding the remaining ½-cup of powdered sugar. Add more milk if mixture is too thick (I added 2 more tablespoons). Cool completely before using.

Assemble the cake: Place one cake layer on a cake stand. Cover with half of the caramel filling and then, chop the cookies and spread over top to evenly cover the caramel frosting. Top with chocolate frosting. Add the second cake layer and cover with the remaining caramel frosting and top with more chopped cookies. Decorate with Dark Chocolate Salted Caramel Toffee Bark.