Preheat oven to 190°C. Line the base and sides of a 2cm-deep 25cm x 30cm Swiss roll pan with baking paper. Using an electric mixer, beat eggwhites until soft peaks form. Add 1/2 cup sugar, 1 tablespoon at a time, beating well after each addition until sugar is dissolved. Add egg yolks, one at a time, beating well after each addition until mixture is thick and creamy.

Sift flour three times. Add butter and sifted flour to egg mixture. Fold through gently to combine. Pour into prepared pan. Smooth top with a spatula. Bake for 7 to 8 minutes or until just firm.

Meanwhile, place a 25cm x 30cm sheet of baking paper on workbench. Sprinkle with remaining sugar. Turn cake onto prepared paper. Peel away lining paper. Using prepared paper as a guide, roll up cake from one short side. Cover with a clean tea towel. Set aside. Allow to cool.

Place ice-cream in a bowl. Set aside at room temperature for 5 minutes or until softened. Add strawberries and stir to combine. Roll out cake. Spread with ice-cream mixture, leaving a 1cm border. Roll up cake from one short side to enclose filling. Cover with plastic wrap. Place in freezer overnight or until firm.

Place chocolate and cream in a heatproof, microwave-safe bowl. Microwave on high (100%) for 1 to 2 minutes, stirring every minute with a metal spoon, or until smooth.

Remove cake from plastic. Place on a plate. Pour over chocolate mixture. Sprinkle with white chocolate. Set aside for 10 minutes to soften slightly. Serve.