1. Preheat the oven to 150°C and line a 23cm round cake tin with baking paper.
2. Weigh the chocolate into a medium sized bowl and place it over a medium sized pan with a little water, ensuring it doesn’t touch the bowl. Place over a medium heat to melt the chocolate.
3. Once the chocolate has melted, whisk in the cocoa powder.
4. In a small pan, gently bring the milk to a simmer, add it to the chocolate mixture and whisk it in.
5. Add in the lemon juice to the chocolate mixture and whisk until well combined. Transfer this mixture to a large mixing bowl and set aside.
6. In an electric stand mixer fitted with a whisk attachment, whisk the whole eggs and 100 g caster sugar on medium speed for about 10 minutes until pale and well aerated.
7. In a small bowl whisk the cream until soft peaks form, then place it in the fridge while you prepare the egg whites.
8. Whisk the egg whites and remaining sugar on a low to medium speed to form stiff peaks, creating a French meringue.
9. Use a spatula to fold the egg yolk mixture into the chocolate mixture in two additions. Fold in the whipped cream, and finally the meringue.
10. Gently mix until just combined. Pour the mixture into your prepared tin and place onto the top shelf in the oven.
11. Bake for 40–50 minutes until the cake has risen. The surface will have cracks and if you gently shake it, the cake will have a full wobble.
12. Leave to cool on a wire rack for about an hour before serving. Lightly dust the top with cocoa powder and serve with cream.