Roll out the pastry on baking paper into a rectangle the size of the baking tray, 4 mm thick. Place it on the tray with the baking paper and prick it several times with a fork.

Cover the pastry with uncooked chickpeas to keep it stable whilst blind-baking. Bake the pastry in the oven at 170 degrees (fan) for 15 minutes. Leave to cool, then remove the chickpeas from the pastry.

For the filling, chop the whole hazelnuts by hand, in a food processor or in a chopper until medium-coarse. Then mix with the ground hazelnuts and the eggs in a bowl.

Melt the butter in a saucepan. Add the sugar and vanilla sugar and heat until the sugar has dissolved.

Add the nut mixture and heat over a medium heat, stirring continuously, until a thin crust forms on the base of the saucepan. Remove the saucepan from the heat.

Spread the jam over the cooled pastry base and spread the toasted nut mixture on top. Bake in the oven at 170 degrees (fan) for 30–40 minutes.

For the glaze, melt the chocolate in a saucepan over a low heat.

Once baked, leave the nut slices to cool. Pour the melted chocolate over the cooled nut slices.