Prepare all ingredients and weigh them. Warm the butter slightly
Break the chocolate into pieces and add to the warm butter. Stir everything with a whisk until the chocolate is melted.
Mix the brown and white sugar, add the vanilla sugar, and the salt and mix everything well. Remove the warm mixture from the heat. Allow the chocolate mixture to cool well.
Cut the vanilla bean lengthwise and scrape out the pulp with a knife. Add the coffee flavoring and cocoa to the chocolate cream.
Beat the eggs briefly and fold into the cooled chocolate cream. This is best done with a spatula.
Now fold the flour into the brownie batter.
Line a small square 20 X 20 cm baking pan with baking paper and fill with half of the batter.
Spread the cookies and some dulce de leche on the dough.
carefully pour the remaining chocolate batter into the mold.
Bake the dough in the preheated oven at 170 degrees convection on the middle shelf for about 20-25 minutes. The chocolate cake should have a crust and still be slightly moist in the center.
If you press on the surface with your finger, it will give a little. The brownie cake should not be baked too long in any case.