Boil the sugar and water in a wide pan without stirring. Reduce the heat and simmer, swirling the pan occasionally until a light brown caramel has formed. Remove the pan from the heat, pour in the cream, continue to simmer and stir over a low heat until the caramel has dissolved, stir in the butter. Place the chocolate in a thin-sided bowl and suspend over a gently simmering bain-marie; the bowl must not touch the water. Melt the chocolate, stir into the caramel. Pour the mixture into a bowl and leave to cool.
Place the chocolate and butter in a thin-sided bowl and suspend over a gently simmering bain-marie; the bowl must not touch the water. Melt the chocolate and stir until smooth. In a bowl, beat the sugar, eggs and salt using the whisk on a hand mixer until the mixture is light and fluffy. Stir in the chocolate butter, mix in the flour.
To fill the ramekins
Transfer the cake mixture to the prepared ramekins. Spoon ½ tbsp of caramel and one chocolate ball into the centre of each.
Approx. 14 mins. in the centre of an oven preheated to 170 °C (convection). The cakes should still be a little runny inside. Remove from the oven, tip the hot cakes out onto plates, dust with icing sugar, serve immediately.