Preheat your oven to 180°C (gas mark 6) and grease a 20×20 cm square baking tin.
Melt the dark chocolate and butter together in a bain-marie or in the microwave, stirring until the mixture is smooth. Allow to cool slightly.
In a large bowl, whisk together sugar, eggs and vanilla extract until light and fluffy.
Fold the melted chocolate mixture into the egg and sugar mixture.
Add the flour and salt, and mix just until the dry ingredients are incorporated into the wet mixture. Do not overmix.
Pour half the brownie batter into the prepared tin. Spread the salted caramel evenly over the brownie batter. Pour the remaining brownie batter over the salted caramel.
Bake in preheated oven for approx. 25-30 minutes, or until brownies are slightly firm to the touch.
Let brownies cool completely in pan before cutting into squares.
Serve the salted caramel brownies with an extra touch of caramel on top, if desired. You can also sprinkle a little extra salt over the caramel to intensify the taste.