Unwrap caramels, and place in a medium saucepan. Add 1/3 cup evaporated milk; cook over low heat until caramels melt, stirring often. Remove from heat, and set aside.
Combine remaining 1/3 cup milk, cake mix, and next 3 ingredients; stir just until blended. Spread half of dough into a lightly greased 9" square pan. (Remaining dough will stiffen as it sits.) Bake at 350° for 10 minutes. Cool in pan on a wire rack 5 minutes.
Pour caramel mixture over brownie layer in pan. Sprinkle with walnuts.
Divide remaining half of dough into 6 portions. Shape each portion into a 4" circle. Place circles over walnuts in pan, overlapping slightly. (Dough will spread during baking.)
Bake at 350° for 25 minutes. Cool completely in pan on wire rack. Cover and chill thoroughly before cutting.
Note: For caramel-flavored cake mix, we used Duncan Hines.