In a food processor, whizz up your nuts, sugar, cocoa and chocolate until you have coarse-ish crumbs. Remove the lid and add your butter and egg yolks. Whizz until it starts to come together. Set your mix aside.
Unravel your pastry sheet and dust another baking sheet with flour. Lay down your pastry and cut the largest possible circle you can. Make 3 incisions in the centre of the pastry. They should meet in the middle to form a star shape.
Throw down your nut chocolate mix in a ring half way between the incisions and the end of the pastry. Bring together in a kind of sausage.
Brush the central triangles with egg white. Bring together the end of the pastry to meet the brushed centre. Repeat until you have 6 sections.
Bake for 30 minutes at 375ºF. Leave to cool slightly.
Serve with vanilla ice-cream and fresh raspberries.