Ganache:

1. Place chopped chocolate in a small bowl. Heat the heavy cream in a small saucepan over medium heat until it begins to gently simmer. 
2. With a small rubber spatula, very slowly stir until completely combined and smooth, silky, and shiny.
3. Refrigerate for about 2 hours.

Chocolate Fondant Cake:

1. Brush all over the inside of the pudding mould with softened unsalted butter. Then coat it with cocoa powder. Tap any excess cocoa powder.
2. In a heat-proof mixing bowl, add chocolate and unsalted butter. And melt over simmering water. Remove the bowl from the heat and stir until smooth.
3. Prepare two bowls and separate the yolk and white.
4. In a bowl of egg yolks, whisk the yolks with half quantity of sugar until the mixture is thick and pale.
5. Pour melted chocolate and butter into egg mixture. And stir until well combined.
6. Sift cacao powder into the mixture, then beat together.
7. In a bowl of egg whites, whisk the whites with remaining sugar. Continue whisking to get to “soft peak”.
8. Add one large spoonful of the egg whites and beat well with the whisk to make the mixture less stiff. Carefully fold in the remaining egg whites. Stir gently and slowly the mixture without breaking the air bubbles up.
9. Pour the mixture into one half of the pudding mould. Put one tablespoon of ganache into the middle. Pour the remaining dough to cover the ganache.
10. Bake in the oven preheated to 355 degrees (180C) for about 7 to 10 minutes until the tops have formed a crust and they are starting to come away from the sides of their moulds. 
11. Remove from the oven, then leave to sit for 2 min before turning out. Then serve the cakes while still warm!