Preheat the oven to 175 degrees Celsius (top and bottom heat). Line a baking dish (approx. 20×30 cm) with baking paper.
Melt the butter over medium heat in a small saucepan. Pour into a bowl.
Add granulated sugar, cocoa, salt, vanilla sugar and whisk together until smooth.
Add the eggs and continue whisking.
Add the wheat flour, use a spatula and gently fold into a smooth batter.
Pour the batter into a bowl and spread it out into an even layer with the spatula.
Bake your brownies in the middle of the oven for about 25-30 minutes. Let cool and set in the refrigerator while you make the caramel.
Add the caramel ingredients to a heavy-bottomed saucepan and bring to a boil, stirring constantly, over medium heat for 10-15 minutes (use a thermometer, 123 degrees is fine). Do the ball test to test if the caramel is cooked enough (pour a little caramel into a glass of cold water, if the caramel can be formed into a soft ball, it is ready).
Pour the caramel over the brownie and let cool to room temperature while you make the garnish.
Dry roast the cashews in a hot frying pan. Then coarsely chop the nuts, sprinkle salt flakes and nuts over the caramel.
Let the cake stand in the refrigerator until the caramel has reached a good consistency for cutting into pieces.
