To decorate the top with caramel drizzle: Place 5 ounces of caramel bits in a microwave safe bowl and add the evaporated milk. Microwave in 20-30 second intervals, stirring between, until caramels are smooth and completely melted. This will take 2-3 minutes.
Allow the caramel to cool completely to room temperature, then drizzle the caramel over the cake.