In the end I decided to go for a really simple cake. A flourless chocolate cake. I've never done one before but it was really simple. Again, you can google it and find loads of recipes.
The only thing difficult about this cake is waiting for it to refrigerate. There may be over 400 calories per slice in it, but you didn't hear it from me!
For the cake:
350g dark chocolate
170g butter (plus a little extra for greasing)
5 large eggs
60g cocoa powder, sifted
1.5tsp vanilla extract
2tbsp cooled espresso
For the ganache:
100g dark chocolate
Lightly butter bottom and sides of a 24cm-round 5cm-deep cake tin and line with baking paper. Dust with cocoa powder.
Put the chocolate and butter in a bowl over simmering water until melted and smooth. Set aside and cool slightly.
In a stand mixer, whisk the eggs, sugar, vanilla, salt and the espresso until pale, frothy and doubled in volume.
When the butter/chocolate mixture is cool enough, reduce the speed on the mixer to the lowest setting and gradually add to it the egg mixture until fully incorporated.
Remove the bowl from the mixer, sift the cocoa into the mixture and fold in with a large spoon or spatula.
Transfer to the cake tin you prepared earlier and bake in a preheated oven on 150 degrees for 40 -45 minutes until a skewer inserted into the center comes out sticky with small sticky clumps. DO NOT OVERCOOK.
Let it cool in the tin for 30 minutes and then invert onto a cooling rack (running a knife around the edges if necessary) and remove the baking paper.
Cool completely, transfer to a cake plate, cover and chill for 6 hours or overnight.
Heat the cream and chocolate in a bowl over simmering water until smooth and shiny. Pour over the cake. Leave to set.
To cut the cake, heat the knife by putting it in a cup of boiling water for a few seconds and wipe dry before cutting.