Ingredients

Step by step

1. Preheat the oven to 180ºC, fan 160ºC, gas 4. Grease two 4cm-deep 20cm sandwich tins with the extra butter, and dust lightly with the extra flour.
2. Put the sugar and eggs in a large heatproof bowl and set the bowl over a pan of simmering water – don't let the bottom of the bowl touch the water. Whisk, using an electric hand whisk, for 15 minutes until the mixture thickens, doubles in volume and creates a 'ribbon effect'. When the beaters are lifted out of the bowl, the mixture should drop from them and leave a temporary trail on the surface (see image A above). Remove the bowl from the pan of hot water.
3. In batches, sift the measured flour on to the mixture, and gently fold in with a large metal spoon. Now fold in the melted butter. Be careful not to overmix. Divide the mixture between the tins, smooth the tops and bake for 25 minutes until golden. Turn out on to a wire rack to cool.
4. Carefully slice the cold sponges in half horizontally with a serrated knife (B) to make 4 sponge layers. Beat the cream with the vanilla sugar until light and fluffy.
5. To assemble, place the bottom layer on a cake stand or plate and spread with a layer of the whipped cream. Layer some berries on top, slicing the strawberries (C), then cover with another layer of cream and put the second sponge on top. Top this sponge with cream only then top with the third sponge. Cover with cream, berries and cream as before, then place the final sponge on top. Cover with the remaining cream and berries. Decorate with the mint leaves and dust with icing sugar to finish, if you like.