Adding fondant to oddly shaped cakes, such as the number three cake takes more skill than adding it to the usual square or round cakes. Use the number three cake mould for measuring the amount of fondant needed to cover the cake. Measuring the cake mould avoids having too little fondant for the cake.
Measure the widest part of the cake at the arcs and the length of the cake mould using the ruler. Add 5 cm (2 inches) to the measurements to each end to avoid mistakes. Record the measurements for later use.
Sprinkle cornstarch on the surface used to roll the fondant. Roll fondant with a rolling pin, using the measurements taken from the cake mould.
Immediately apply crumb coating or buttercream icing to the cake. The icing or crumb coating acts as a glue attaching the fondant to the cake.
Slide your hands underneath the fondant and lift the fondant off the surface. Carefully place the fondant over the cake.
Smooth the fondant over the cake in quick circular movements using both hands. A fondant smoother can be used to smooth the top and the outside edges of the cake.
Smooth and tuck the fondant on to the inside of the arcs. Smooth the inside of the arcs in a swooping motion following the shape of the arcs.
Trim off the fondant at the bottom edge of the cake with a knife.
Decorate the number three cake and serve.
The back of a pair of scissors can be used to to smooth the sides and inside the arcs on the cake.
Cover rolled fondant with cling film to keep it from drying out while adding crumb coating to the cake.
Cover imperfections around the bottom of the cake with icing to give a professional look to the cake.