1 package dark chocolate cake mix
3/4 cup butter or margarine, melted
2/3 cup evaporated milk
12 ounces caramels
6 ounces semisweet chocolate pieces

Lightly grease and flour 13 X 9 pan. Mix together cake mix, melted butter and 1/3 cup of evaporated milk in medium size bowl.  Spread half of mixture (1 1/2 cups) evenly in the prepared pan.  Bake in 350 degree oven for 6 min. Melt caramels with remaining 1/3 cup evaporated milk in small saucepan over low heat. 
Sprinkle chocolate pieces over baked mixture; then drizzle caramel mixture on top. Spread remaining cake mixture on top of caramel. Bake in 350 degree oven for 18 minutes longer. Remove pan to wire rack to cool completely. Cut into bars and serve at room temperature.