Preheat the oven at 160ºC fan / 180ºC.
Melt the butter and dark chocolate in a small saucepan.
Whisk together the melt butter and dark chocolate with caster sugar in a bowl.
Add the eggs in the bowl one at a time whilst continuing to whisk.
Sieve the plain flour and cocoa powder in to the mixture and fold in with a spatula.
Pour the mixture in to a 7″ inch lined square cake tin.
Pour dots of salted caramel in to the top of the batter and with a cocktail stick make swirls with the caramel.
Place in the oven and bake for 25-28 minutes.
Once baked, allow to cool in the tin, before removing and slicing into squares.