Chocolate Sponge

• Prepare a pan and preheat the oven. Grease and line the base and sides of a 23cm (9-inch) springform pan. Preheat your oven to 180°C (350°F).
• Whip the eggs & sugar. Add the eggs, sugar, light brown sugar and vanilla extract into a medium-sized bowl. Using a hand-held electric whisk, whip on medium-high speed until the mixture is light and creamy, about 4 minutes.
• Add the dry ingredients and fold through. Sift into the egg bowl the flour, cocoa powder, baking powder, and espresso powder and add the salt. Mix at low speed until just a few flour streaks remain.
• Add the melted chocolate. Add the melted chocolate into the batter and fold through with a rubber spatula. Make sure to scrape the bottom of the bowl as you fold until the ingredients are combined and smooth.
• Pour batter into baking pan and bake. Pour the batter into the prepared springform pan. Tap the pan firmly on the work surface a couple of times to release any air bubbles. Bake for 15-20 minutes until the centre springs back. Remove from the oven and place pan on a wire rack and leave to cool to room temperature.