Melt the butter and chocolate over a water bath. Add the espresso and chopped coffee beans and mix.
Allow the butter and chocolate to cool slightly.
Beat the egg with the sugar, cardamom, vanilla sugar and salt.
Add the chocolate butter to the egg and fold in.
Fold the cocoa flour into the dough by the tablespoonful.
Pour the batter into the cake tin.
Bake for approx. 25 - 30 minutes and then leave to cool.
Cut the brownies into pieces.
For the tahini caramel sauce
Mix the sugar and pinch of salt with water in a small saucepan and bring to the boil. Stir until the sugar has dissolved.
Turn the heat to medium and let it bubble for about 15 minutes. Do not stir. (The colour changes and becomes slightly golden).
Turn off the cooker. Remove the pan from the cooker. Stir in the tahini completely. Then stir in the cream. The sauce is still a little liquid, but will become more solid as it cools. It is best to spread the sauce over the brownies while they are still lukewarm.
Sprinkle fleu de sel / sea salt flakes over the brownies with sauce to taste.