- 1 8-in. (20 cm) round Hazelnut Sponge Cake
- Trim the top of the cake, if necessary, to make it level. Turn it upside down. Cut it in half horizontally to split into 2 layers.
- Brush both halves with syrup to moisten.
- Using a pastry bag with a medium plain tip, pipe the ganache onto the bottom layer, making a spiral that starts in the center and covers the layer completely.