Cassata cake

Make the chocolate-and-coffee ganache well in advance as it needs to cool and firm to a spreadable consistency.
Melt the chocolate in a double boiler or carefully in the microwave. Bring the cream to a boil, remove, stir in the coffee and mix well with the chocolate.
Add the butter, block by block, stirring until it has all melted. Set aside to cool and firm.
For the cake, grease and line the bottom of a loaf tin 25cm x 10cm. Sift together the flour and baking powder.
Whilst beating the egg whites, slowly add 2 tablespoons of sugar at a time, until the mixture is firm and glossy and all the sugar has been incorporated.
Gently mix the egg yolks and orange zest into the egg whites. Fold in the flour and baking powder without losing volume.
Very gently fold in the melted butter, taking care not to overbeat. Pour the mixture into a prepared tin and bake at 180°C until a skewer inserted comes out clean, about 30 minutes.
Allow to cool in the tin for 10 minutes then remove and cool completely. Slice the sponge cake into three layers horizontally.
Place one layer on a tray that will fit into the refrigerator and spread it with half the ricotta mixture. Continue alternating the cake and ricotta mixture – the last layer should be cake.
Wrap it in clingfilm and allow it to firm in the fridge for an hour or two. Remove it from the refrigerator and ice it completely with the chocolateand- coffee ganache, then return it to the refrigerator.
Remove it again 30 minutes before serving and decorate it with home-made truffles, as shown, or with anything you choose.
Cook's note: the beauty of this cake (the recipe originates in Sicily) is that you can make it as simple or as complicated as you like by either buying the sponge cake or making it yourself.