This really is a good cake. Easy too. It's rich and dense, and a little goes a long way - but in my opinion that's what chocolate cake should be all about. The covering and decoration is optional - a chocolate buttercream would be a good alternative in place of the ganache - but the least I would do is slice and fill it.
For the cake:
300g light brown sugar
200g plain flour
1 tsp baking powder
300g dark chocolate
For the ganache:
125ml double cream
250g unsalted butter, diced
500g plan chocolate (50 - 70% cocoa solids)
Method for the cake
1. Heat your oven to 160C/fan 140C.
2. Line the sides and base of a 20cm round cake tin with baking parchment.
3. Using an electric whisk or mixer, beat together butter and sugar in a bowl until pale and fluffy.
3. Beat in the eggs one at a time, add 1 tbsp of the flour after each egg.
4. Melt the 300g chocolate in a bowl set over a pan of simmering water. Once melted, leave to cool slightly.
5. Pour the chocolate into the cake mixture, beating as you do so.
6. Fold in the rest of the flour with a large spoon.
7. Pour in to your prepared tin and bake for 1 hour 30 minutes.
8. Leave in the tin to cool completely and then take out of the tin.
9. Split the cake horizontally.
10.Fill and cover with either chocolate buttercream or the ganache, below.
Method for the ganache
1. Heat the double cream in a saucepan until it just comes to the boil, then remove from the heat.
2. Melt the butter and the chocolate in a bowl over a pan of simmering water.
3. Pour the cream over the chocolate and butter, and stir to combine.
4. Now beat the ganache well with a wooden spoon until it is rich and glossy.
5. Use this ganache straight away for pouring over the cake - I'd advise you to 'crumb coat' the cake first with some chocolate buttercream.