Double Chocolate Cake Bars

Directions

1. 1
   Preheat the oven to 375°F. Grease and line an 11 x 7 inch jellyroll pan with parchment paper.
2. 2
   Place eggs and sugar in a large heatproof bowl over a pan of hot water. Whisk with an electric mixer until mixture has doubled in volume and is thick enough to leave a trail. Remove bowl from heat. Whisk for 5 minutes, until cool.
3. 3
   Sift in flour and add white and semi-sweet chocolate chips, reserving 2 tbsp of each chocolate. Fold together with a large metal spoon.
4. 4
   Pour the mixture into the pan and tilt to level surface. Bake for 15-20 minutes, until golden and springy to the touch. Turn out on to a wire rack. Remove the parchment paper.
5. 5
   Sprinkle top with reserved chocolate chips and allow to cool. Dust with cocoa powder and cut into 12 bars. Best eaten within 2 days.