Grease 6 small ramekins thoroughly with butter. (I used 6.8cm round ramekins).
Dust the with bottom and sides with cocoa and place on a baking tray and set aside.
First make the salted caramel.
Place the butter and brown sugar in a saucepan on a medium to high heat.
Once the butter has melted, add the milk and bring to the boil.
Boil for at least 2 minutes before removing from the heat.
Add the salt and allow to cool while you make the lava cake mixture.
Preheat the oven to 210°C (410°F)
Melt the butter, salted caramel chocolate and dark chocolate together.
Beat the eggs and icing sugar together until fluffy.
Mix in the chocolate mixture.
Finally fold in the flour.
Pour around about two tablespoons of mixture into each ramekin.
Place a heaped tablespoon of salted caramel sauce into the middle of each.
Top each ramekin with the remaining lava cake mixture to cover the salted caramel.
Place in the baking tray in the oven for around 10 minutes. Check them at 7 minutes. The tops and sides will be set and the top very lightly springy. The middle will be wobbly.