2 tbsp unsweetened cocoa powder, plus extra for dusting
125g/4½ oz/2⁄₃ cup, plus 2 tbsp caster sugar
250g/9oz dark chocolate, roughly chopped (dairy free if needed)
100ml/3 ½ fl oz/generous 1⁄₃ cup olive oil, plus extra for greasing
100ml/3 ½ fl oz/generous 1⁄₃ cup strong brewed coffee, cooled
1 tsp vanilla paste
1 tsp fine sea salt
6 large eggs, separated
80g/3oz/ ¾ cup ground toasted hazelnuts (see Top Tip)
1 Preheat the oven to 180°C/160°C fan/gas 4. Mix the cocoa powder with the 2 tablespoons of caster sugar. Grease a 23cm/9in loose-based round cake tin with oil and line the base with a circle of baking paper, then brush more oil on top. Tip the cocoa powder/sugar mixture into the tin and rotate the tin around so you have a thin coating all over. This will help it to rise.
2 Put the chocolate, olive oil, coffee, vanilla and salt into a large, heatproof bowl and place over a saucepan containing a little water (making sure the water isn’t touching the bowl). Put over a low heat and gently melt everything together. Set aside to cool slightly.
3 Put the egg whites into the bowl of a stand mixer (or use a large bowl and an electric whisk). Whisk on a slow speed for around 2 minutes until the egg whites turn foamy. Turn the speed up to medium and slowly add the remaining 125g/4½oz/ ²/³ cup of sugar, 1 tablespoon at a time, until you have a smooth, thick, glossy meringue – don’t overwhisk, otherwise it’ll be difficult to incorporate.
4 Whisk the egg yolks into the cooled chocolate mixture, then stir in the ground hazelnuts until combined. Stir in a third of the meringue mix to loosen the chocolate batter. Tip in the rest of the meringue and fold in using a spatula until you have a light chocolatey batter. Tip into your prepared tin and spread it evenly.
5 Bake for 40–45 minutes until risen and a skewer inserted into the centre comes out clean. Run a small, sharp knife around the edge of the cake when it’s hot as this will help it to sink evenly – the sponge will sink and crack significantly as it cools. Leave to cool completely in the tin, then turn out, dust with cocoa powder and slice to serve.
Store in an airtight container (or wrapped) for up to 4 days.
TOP TIP If you can’t find any ground toasted hazelnuts, buy some blanched hazelnuts, toast them in a hot frying pan and leave to cool, then blitz them to a powder in a food processor.
The featured recipe is from Liberty Mendez’s I’ll Bake: Something delicious for every occasion (Pavilion Books) – out now.
Recipe photography: Lizzie Mayson