Melted butter, to grease
1 x 500g packet chocolate cake mix
180g butter, melted
2/3 cup evaporated milk
2 x 200g packets caramel lollies, such as Columbines
1 cup chopped walnuts
1 cup milk chocolate bits
Preheat oven to 180C. Grease a 30 x 20 x 5cm slice tin; set aside.
Put cake mix, melted butter and 1/3 cup of the evaporated milk in the large mixing bowl of an electric mixer and beat on medium speed until smooth. Spread 3/4 of dough in prepared tin. In a larger heavy-based saucepan, cook and stir caramels and remaining evaporated milk over medium-low heat for 6-8 minutes until caramels are melted and mixture is smooth.
Pour caramel mixture over dough. Sprinkle with nuts and chocolate pieces. Dot remaining dough over layers in tin.
Bake for 25 minutes. Cool in tin on a wire rack. Cut into squares and serve.