Brush some butter in a ramekin, then dust with cocoa powder (you can also use caster sugar) 

Melt the chocolate and butter in microwave for about a minute, mix well.

In another bowl, mix egg, sugar and salt together, then add in chocolate sauce, mix well. Then sift in flour, mix well.

Pour the batter into ramekins, pop in preheated oven at 220C, bake for 8 to 10 minutes. *the surface of the cake should be set

Let it cool for 1 to 2 minutes, unmold it. Dust with icing sugar and serve with ice-cream and fruit. Enjoy!