Rich hazelnut brownies with vanilla creme fraiche

Name: Rich hazelnut brownies with vanilla creme fraiche
Prep time: 30 min
Cook time: 35 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: 450g caster sugar; 4 eggs; 250g butter, melted; 1 vanilla bean, seeds scraped; 170g plain flour; 115g cocoa powder; 2.40 gm salt; 150g hazelnuts, roasted, chopped; 400g dark chocolate (65% cocoa), chopped; 200g creme fraiche; 1 vanilla bean, seeds scraped, extra