Heat oven to 350°F (325ºF for dark or nonstick pan). Grease and lightly flour 12-cup fluted tube cake pan, or spray with baking spray with flour.
Make and bake cake as directed on box for fluted tube pan. Cool 10 minutes; remove from pan to cooling rack. Cool 15 to 30 minutes.
Meanwhile, in 2-quart saucepan, heat caramels and evaporated milk over low heat, stirring frequently, until caramels are melted. Stir in cashews. Serve slices of warm cake topped with warm cashew-caramel sauce. Store cake loosely covered. Cover and refrigerate any remaining caramel sauce.