Hazelnut torte

• butter, for greasing
• 250 g raw sugar
• 250 g hazelnuts, plus extra for decorating
• 8 eggs separated, room temperature
• 1 pinch salt
• 40 g water
• 60 g cornflour
• 40 g plain flour
• 1 tbsp baking powder

Filling

• 1 egg
• 100 g caster sugar
• 10 g instant granulated coffee
• 500 g pouring (whipping) cream, chilled
• desiccated coconut, for decorating