• Hazelnut sweet pastry:
• Rub the flour, the icing sugar, the ground hazelnuts, the salt and the cold butter with the food processor paddle.
• Add the egg and mix until slightly combined. Bring together into a ball and smear (fraser).
• Roll out to 2.5mm thick and put in the freezer for 30 min.
• Cut 2 strips 4cm wide and 27cm long and a round the size of the ring then line the ring (put the pastry back in the freezer before handling).
• Leave in the freezer for at least 30 min.
• Bake for 8 min at 170°C.
• Hazelnut cream:
• Cream the softened butter with the sugar.
• Add the ground hazelnuts, then the egg.
• Pour the cream into the pre-baked tart bases, add the crushed hazelnut and bake for 10-15 min at 160°C.
• Leave to cool.
• Hazelnut butter:
• Toast the hazelnuts for 10-15 min at 170°C.
• When they have cooled, blend them until you get a paste.
• Add the salt.
• Hazelnut praliné:
• Toast the hazelnuts for 10-15 min at 170°C.
• Make a dry caramel, pour it onto a tray covered with baking paper and leave to cool.
• When everything is at room temperature, blend in the food processor until you get the right texture and add the salt, without blending.
• Spread a layer over the hazelnut cream then leave to set in the fridge.
• Hazelnut diplomat cream:
• Whisk the egg yolk and the egg with the sugars and add the flour.
• Heat the milk with the vanilla powder and pour it over the egg mixture while whisking.
• Return to medium-high heat and whisk without stopping until it thickens.
• Cook for a further 10s after the bubbles appear.
• Off the heat, add the butter then the hydrated gelatine.
• Add the hazelnut butter then leave to cool to around 20°C.
• Whip the cream and fold it into the set pastry cream.
• Spread over the hazelnut praliné.
• Hazelnut gélachoc cream:
• Hydrate the gelatine in cold water at least 10 min beforehand.
• Heat the cream with the sugar and the hazelnut butter.
• Pour over the gelatine and the chocolate.
• Add the rest of the cold cream and blend.
• Pour into another dish, cover with cling film touching the surface and chill overnight.
• The next day, whisk the set cream in the food processor and when it is loosened add the water and continue whisking.
• Pipe onto the tart starting from a 5cm circle.
• In the centre add some praliné and a few hazelnuts for decoration.