Steps
1. Preheat your oven to 425°F (220°C).
2. Melt the dark chocolate and butter together in a heatproof bowl over a simmering pot of water (double boiler).
3. In a separate bowl, whisk the egg, egg yolk, and sugar until light and frothy.
4. Combine the melted chocolate mixture with the egg mixture, add flour and salt, and mix until smooth.
5. Grease a ramekin and pour the batter in, filling it about 3/4 full.
6. Bake for 12-14 minutes until the edges are firm but the center is still soft.
7. Meanwhile, prepare the chocolate cloud by whipping the heavy cream until soft peaks form. Fold in the melted dark chocolate and cocoa powder until smooth.
8. Using liquid nitrogen, pour it over the chocolate cream mixture while stirring until it reaches a fluffy, cloud-like consistency. Quickly spoon it onto the baked lava cake.
9. Serve immediately with warm chocolate sauce poured over the nitrogen-frozen cloud to create a dramatic melting effect.