Step 1

Heat the oven to 160°C/140°C fan/gas For the meringue, put the egg whites in a large clean bowl and, using an electric hand mixer, whisk to stiff peaks. Gradually whisk in the 275g caster sugar, 1 tbsp at a time, to make a stiff, glossy meringue, then whisk in the cornflour and vinegar.

Step 2

Spread the mixture evenly in the prepared tin and bake for 25 minutes until the surface is lightly browned. (It will puff up a lot but don’t worry, it will go down again as it cools.) Remove from the oven and set aside for 10 minutes to cool slightly.

Step 3

Lay a large sheet of non-stick baking paper on a work surface and sprinkle with the remaining 2 tbsp caster sugar. Still on its tray, flip the meringue onto the sugary paper and lift off the swiss roll tin. Ease the paper away from the sides of the meringue only and leave to cool.

Step 4

For the mocha cream, put the cream, coffee powder, sugar and cocoa in a large bowl and use a electric hand mixer to whisk it into soft peaks. Dice the bananas and toss with the lemon juice.

Step 5

Carefully peel the baking paper away from the meringue. Spoon over the toffee sauce and spread it out, right up to the edges on 3 sides, leaving a 2.5cm border on the short edge furthest away from you. Spread with the mocha cream, then scatter over the bananas and lightly press them into the cream.

Step 6

Starting with the short edge closest to you, and using the edge of the base paper to help you, roll up the meringue as you would a swiss roll. Leaving the roulade wrapped in the paper, carefully lift it onto a large clean baking sheet and chill for at least 1 hour. This will help it to hold its shape when you slice it.

Step 7

To serve, unwrap the roulade, dust with icing sugar and cocoa powder, then gently lift onto a serving plate.