Method

​1 Preheat the oven to 180°C/fan 160°C/Gas mark 4. Line the bottom of a 23cm spring form cake tin with baking parchment.

2 For the cake sponge: melt the dark chocolate with the butter in a microwave and then set aside to cool slightly. Be careful not to burn the chocolate.

3 Whisk the 4 egg whites until firm, then gradually add 100g (4oz) of the caster sugar and whisk until the whites are holding their shape and peak - but not stiff. Remove this bowl and set aside

4 In a new bowl whisk the 2 whole eggs and 4 yolks with the rest of the sugar (75g) and the vanilla extract. Gently fold in the melted chocolate mixture.

5 Lighten your new chocolate-egg mixture with some egg whites -just dollop a large spoonful in and stir briskly. Then gently fold in the rest of the whisked whites in about three goes.

6 Pour into the prepared tin and bake for 35-40 minutes. The cake should be risen, cracked and the centre no longer wobbly on the surface. Cool the cake in its tin on a wire rack. Note that the middle will sink as it cools and the sides will break away slightly. I love this very much "rough and ready" look and this is the style of the cake.

7 Carefully remove the cake from the tin and place it on a plate or cake-stand.

8 For the topping: melt the chocolate and leave it to cool a little. Whip the cream until it is firming up and aerated but still soft. Add the vanilla extract and fold in the melted chocolate. Fill the centre of the cake with the chocolatey cream. Ease it out gently towards the edges of the cake with using a spatula. Arrange the raspberries or your favourite fruit on top.