Measure around the outside and then the height of your cake. Add another 1.5cm (1/2") to each measurement and that will be the size fondant rectangle you will need. Dust the workbench with a little cornflour (corn starch) and using a large rolling pin roll out the fondant until quite thin in a long rectangle that is at least as long and wide as your measurements. Use a sharp knife (or pizza cutter) to cut the rectangle to the required size.



In the middle section of the fondant at the bottom cut out a half circle that will be the open mouth area.around 6 cm at the biggest and tapering down to be 12cm wide.



Working quickly wrap the grey fondant around the cake and join it together at the back trimming off any overhang where the fondant joins. There should be around 1.5 cm overhand around the top of the cake which is where the brain will sit. It will act as a dam to hold the brain and raspberry sauce.



I placed some foil in a couple of spots to hold up the fondant while it dried. Press the fondant into the eye socket areas and around the mouth, leaving enough black showing for the teeth to be inserted later. Make sure that the fondant covers the bottom of the cake evenly and no ganache is showing. Press around the nose area, using the cake decorating tool press in the nostrils until you are happy with the shape. Add an indent with the back of the cake tool in the middle of the nose. The truffle mixture underneath should have a little give at this stage and you can still move it around a little to get your desired shape.



Mix a small amount of the grey fondant with a little water to make a thick paste. Place a little paste onto the eye area and press in the eyes. If they are a little big, quickly remove them and trim until you are happy with the size.



Roll out a small amount of fondant and roll as thin as possible to make eyelids. Cut to shape and press onto the eyes covering the top half, using a cake tool smooth the edges as much as possible in the corners to make the join look as seamless as possible. Don't stress too much about the top it will be covered with the eyebrows.



Take another piece of fondant and shape it into a long log. Use a little more of the fondant mixed with water to 'glue' this log into place. Use the cake decorating tool to shape the log into an eye brow. I made an indent on each side just above the nose and then used the sharp side of the tool to make long shallow strokes in the fondant to look like hair. Place a food safe item between the eye and brow to hold in place while it dries (I used some folded foil).



Make more long shallow 'hair' indents in the fondant around the cheek area. Then use the same technique using shorter strokes to give the lips texture.



Using a brush paint on a very sheer small amount of white food color to the lip, upper cheek (under the eyes) and middle brow area.



Allow to dry for a while until the fondant is firm to touch.