Adjust rack to center position of oven and preheat to 350°F. In a small pot set over medium-low heat, combine cocoa, sugar, brown sugar, and coffee. Cook, stirring occasionally, until sugars are dissolved and mixture is hot. Keep warm.
Unwrap Riesen candies and evenly space on the bottom of an 8- by 8-inch square glass baking dish.
Prepare cake batter by whisking together sugar, flour, cocoa powder, baking powder, baking soda, and salt together in a large bowl. Blend in eggs, milk, oil, and vanilla. Beat at medium speed for 2 minutes.
Slowly pour cake batter over candies. Carefully and evenly pour warm coffee mixture over cake batter. DO NOT STIR! Bake for 45 minutes or until the cake layer is firm (the cake will float to the top of the sauce while baking). Cool for 15 minutes before serving warm topped with vanilla ice cream, if desired.
A glass baking dish is recommended because the Riesen caramels will stick to the bottom once the chocolate cobbler cools, and it's easier to scrape them off of a glass dish than a metal pan that may scratch.