White Chocolate & Raspberry Marquise

Preheat oven to 160°C. Grease two 20x5cm-deep round cake pans and line bases with baking paper.

Place butter, 250g of the chocolate, 1 cup of water and sugar in a medium saucepan and stir over low heat until melted and smooth. Cool for 10 minutes.

Stir in egg and vanilla. Sift the flours over the chocolate mixture and stir until combined. Divide equally among cake pans and spread evenly. Tap cake pans on bench to remove air bubbles. Bake for 35-40 minutes or until cooked through when tested with a skewer. Stand for 5 minutes. Turn cakes out onto a wire rack to cool.

Melt remaining 100g chocolate in a heatproof bowl over a saucepan of simmering water. Stir until smooth. Place a 40cm-long sheet of baking paper on a flat surface. Spread chocolate thinly with a palette knife, leaving a 6cm border. Starting at the short side, roll up tightly, enclosing chocolate. Chill for 30 minutes to set.

To make ganache, place chocolate in a bowl. Heat cream in a small pan over medium heat. When cream just comes to the boil, remove from heat and pour over chocolate. Stir until chocolate is melted and smooth. Set aside, stirring occasionally, for about 40 minutes or until of spreadable consistency.

When cakes are cooled, cut in half horizontally to form 4 layers in total. Place 1 layer on a serving plate, then spread with 1/2 cup of the ganache and sprinkle with some of the raspberries (halving if large). Continue layering with remaining cake, ganache and raspberries (reserving some for decorating). Cover sides of cake with remaining ganache. Gently unroll chocolate roll, which will break into shards. Decorate cake with shards and remaining raspberries. Serve.