1. Preheat the oven to 160°C and line a large, deep baking tray with non-stick baking paper.
2. In a medium glass or metal bowl, over simmering water, or in a bain marie, melt the 350g plain chocolate and butter together. Stir in the cocoa powder, drinking chocolate powder, and espresso.
3. In a mixer, beat the eggs and both sugars together. Add the ground almonds, flour, and baking powder and mix together until just combined, then pour in the melted chocolate mix. Add everything else and stir together. Pour into the baking tray and cook for 20-25 minutes until set but still gooey in the middle.
4. Allow to cool and cut into wedges. Serve with some great ice cream and more chocolate sauce.
Recipe courtesy of Kenwood's Around the World in 80 Plates