Once the cake is completely cooled, use a serrated knife to carefully level the cake.
Place a dab of buttercream on a square cake board or appropriately sized plate. Place the single layer matcha cake on top, pressing down slightly to adhere.
Using an offset spatula, frost the matcha cake with a layer of vanilla buttercream, smoothing the sides as you go.
Chill the cake briefly in the fridge or freezer, about 10 minutes.
Fill the first piping bag fitted with a multi-opening grass tip with the matcha buttercream. Pipe the sides of the cake with “fur” – hold the piping bag at a 90 degree angle against the sides of the cake and squeeze piping bag, creating fur. Cover the sides with fur!
Looking down at the top of the cake, pipe a semi-circle of matcha buttercream fur, basically leaving a half-circle for Totoro’s vanilla tummy.
Pipe the entire top of the cake with the matcha buttercream:
Using the vanilla buttercream, fill in the tummy with fur. Store any leftover buttercream in the fridge, covered, for another use, for up to 1 week.
Now onto the fondant! Make 3 inch long pointy white ears. Cut a wooden BBQ skewer in two and insert each piece into an ear. Roll out the fondant. Using the clean edge of a piping tip, cut out circle shapes for the eyes in both white and black. Use a tiny drop of water to adhere the black circle to the white circle for the eyes. Hand shape a nose, and using a sharp paring knife, cut out the shapes for whiskers and the “stitches.” Punch out semi-circle shapes for the tummy markings.
Insert the ears into the top of the cake, and add all of the fondant bits!