Based on a Nigella Lawson recipe.
Melt together 250g unsalted butter, 95g caster sugar, 95g brown muscovado sugar, 250g dark chocolate,
2 tsp instant coffee granules and 370ml water, stirring until it is nice and smooth. Let cool for a few minutes,
then stir in 185g self-raising flour and 30g cocoa powder, beating until it is smooth and glossy again, then beat
in 2 large eggs. Butter a 23cm springform cake tin and line the base with a disk of baking parchment. Pour about
half the chocolate mixture into the pan, then cover with 250g raspberries. Pour the rest of the mixture on top,
and bake in a 180°C oven for 40-45 minutes. Remove from the oven and let stand for 15 minutes, before removing
the sides of the tin. Don’t attempt to remove the cake from the base! When ready to serve, dust the top with
icing sugar and accompany with more fresh raspberries and crème fraîche.