In your mixing bowl, whisk the brownie mix together. Make a well and add the egg. Gently start mixing inwards going outwards with your mini whisk. Add the water and vegetable oil. Mix until it is all incorporated.
Bake for 35 minutes at 350F/180C. (Every oven heats differently, monitor your cake from 30min). It is ready when the toothpick inserted comes out almost clean.
Once your brownie is out of the oven, let it cool down for at least one hour. Then, unmold, serve with the salted caramel sauce.
SALTED CARAMEL SAUCE
In a medium saucepan, melt butter on low. When it is almost melted, add at once, both sugars, the heavy whipping cream, vanilla extract and salt. Carefully bring it to a boil. Continue stirring until the caramel thickens about 8-10min. Then let it cool down.
Serve with the chocolate brownie and add a sprinkle of Sel Gris on top. Enjoy & Bon Appétit!