Pre-heat the oven to 200°C, gas mark 6. Cut the Swiss roll into 4 large slices, place onto a baking sheet lined with greaseproof paper.
Sprinkle each Swiss roll with a tablespoon of Marsala or sherry. Top each Swiss roll with a few slices of banana.
Gradually add the caster sugar a little at a time, still whisking until the meringue has glossy peaks.
Now assemble the Alaska, put on large scoop of Graham’s Traditional Vanilla ice cream on each sponge base. Then pile the meringue mixture on top and over the sides, completely covering the cake and ice cream.
Bake in the oven for about 4 minutes, just until the meringue is lightly browned. Dust with a little icing sugar and serve immediately.