Many cakes look more appealing with a shiny fondant surface opposed to the matte finish that is commonly associated with rolled fondant. Bakers tend to use confectioner's sugar to keep the fondant from sticking on the rolling pin, similar to using flour when rolling biscuits. The powdered sugar leaves the visible fondant dull and less than vibrant. There are many methods for making the fondant covering shiny and glossy, and most likely, you have what you need to do this already in your pantry.
Rub your hands with shortening and smooth your fingers lightly over the fondant on the cake to make it glossy. Be careful not to press too hard as you may create finger impressions on the cake.
Use a paintbrush to apply a very thin layer of nonstick cooking spray on the fondant. Another method of brushing includes using only water or a one-to-one ratio of vodka brushed on the fondant. The alcohol evaporates but leaves a sheen when using the vodka method.
Refrigerate the completed cake as another option to create a glossy appearance to fondant. If you prefer to only have a portion of the fondant shiny, refrigerating the entire cake is not the best option.
Brush luster dust over the cake fondant to make it shiny, resulting in a glittering sheen. This method requires the use of even strokes and a small amount of dust to prevent getting an uneven amount on the cake fondant.
Steam the fondant using a handheld clothing steamer to create a glossy look to fondant as another alternative. Use caution so as to not burn your fingers with the steam, or hold the steamer in one place for too long to prevent watery fondant and streaking colors. Steaming also rids fondant of excess confectioner's sugar.