Ingredients
Cake 
130g plain flour 
100g cocoa powder, divided 75g and 25g 
2 tsp baking powder 
1 tsp bicarbonate of soda 
270g caster sugar, divided 200g and 70g 
4 eggs, separated  
120ml vegetable oil 
120ml coffee, cooled slightly 
1 tsp vanilla extract 

Chocolate sauce 
300ml double cream 
160g dark chocolate 
120g milk chocolate

Method
Put a baking tray tin to the oven and turn the oven on to 180c.  Thoroughly grease a Bundt tin. 

In your mixer put the egg whites and start to mix.  When they have formed soft peaks start to add the sugar a tbsp at a time mixing well between each spoonful.  This will take a few minutes. 

Meanwhile put the flour, 75g cocoa powder, baking powder, bicarb and 200g of the sugar into a bowl. Add the egg yolks, vegetable oil, coffee and vanilla extract and mix until just combined with a large metal serving spoon.  Take one spoonful of the egg whites and mix through.  Now put the rest of the egg whites in and carefully fold in.  You do this by running the spoon around the edge and cutting through the middle, then turn your bowl and repeat.  You don’t want to knock out the air but do want it thoroughly combined. 

Pour the mixture into your tin and put into the oven on your baking tray.  This cake will take around 40 minutes to bake although check after 35 minutes, you want a cocktail stick to come out clean. 

Let the cake cool a little in the tin - at least 20 minutes.   

Meanwhile finely chop up your chocolate and put into a large heatproof dish. 

Heat your cream up slowly until hot but not boiling.  Pour over the chocolate and leave for a minute or so before you stir together. 

Take the cake out of the tin and put onto a serving plate with a lip.  Pour the chocolate sauce in the hole.  There should be enough sauce to fill the hole to the top and fall down the sides a little.  You now want to put the remaining cocoa powder into a tea strainer or fine sieve and dust all over the top.  The sauce should now be hidden and will only reveal itself when you cut into the cake.