Place wire rack on shelf level 2 and preheat the oven on Steam at 100⁰C. Grease and line three 20 cm round cake tins.
Place all of the cake ingredients, except the boiling water into a large mixing bowl. Using a wire whisk, whisk the mixture until well combined. Add the boiling water and whisk together.
Pour the cake mixture evenly into the prepared cake tins. Cook the cakes for 20 minutes. Remove the cakes from the oven and allow to cool in the tins for 10 minutes. Remove the cakes from the tins and allow to cool uncovered.
For the white chocolate ganache: place chocolate and cream in small solid stainless steel tray. Cover with plastic wrap. Place in oven and select Steam 50⁰C. Melt chocolate for 10 minutes. Whisk the mixture until smooth and glossy. Place in the refrigerator until ganache is of a spreadable consistency, stir every 5 minutes.
To assemble cake: place one cake layer on to serving plate. Using a knife, even the top of the cake if required.
Spread 1/3 of the ganache on the cake and top with another layer of cake. Spread another 1/3 of the ganache and top with the third layer of cake. Gently press layers together, making the ganache come out at the edges.
Use a palette knife to even the ganache. Make a cake collar with a piece of baking paper greater than the circumference of the cake. Fold the paper into thirds, length ways. Wrap collar around the cake and press gently to the sides. The collar will keep the cake secure while setting in the refrigerator. Refrigerate for a ½ hour. Leave the last 1/3 of the ganache on the bench.
Use remaining ganache to coat the top of the cake and sides. Decorate with white chocolate truffles.
