For the brownies
- 500 g chocolate couverture
- 250 g butter
- 6 eggs, medium
- 350 g granulated sugar
- 1 teaspoon(s) vanilla extract
- 300 g all-purpose flour
- 50 g cocoa powder
- 1 pinch salt
- butter, for the pans
- cocoa powder, for the pans
For the chocolate hazelnut frosting
- 250 g butter, at room temperature
- 200 g icing sugar
- 350 g hazelnut chocolate spread
To assemble
- 50 g hazelnut chocolate spread
- 2 tablespoon(s) seed oil
- 30 g hazelnuts, toasted and finely chopped