This dessert closes our tour around gourmet potato dishes. What better way to conclude it than with a royal dessert? This was inspired by Prince William's groom's cake, which happens to be his favorite: chocolate biscuit cake. Potato biscuits are torn and mixed in a chocolate candy bar-like mixture, topped with sweet potato mousse and chocolate-glazed potato biscuits. Get ready for the most decadent dessert you've ever had!