Hazelnut and chocolate

Mix the praline with the caster sugar, the egg yolks and the eggs in the food processor using the beater. Whisk the egg whites adding the powdered egg whites with the cream of tartar and add the sugar at the end in three stages. Melt the couverture and the butter. Mix. Sieve the cocoa powder and the flour together. Mix part of the egg whites with the couverture and add to the part with the praline. Add the dry ingredients. Add the remaining beaten egg whites. Bake on a Silpat at 200ºC for about 10 minutes. Freeze and cut into discs. 

Homogenize the butter with the hazelnut paste. Add the sugar and the egg. Sieve and mix in the flour and the hazelnut powder. Finish mixing and set aside in the refrigerator. Spread out to a thickness of 2 mm. Cut out discs. Bake between two Silpain baking sheets at 160ºC for about 20 minutes. Set aside.  

Heat the milk with the sugar. Mix the egg yolks with the egg whites and the cornflour. Pour the milk over the eggs. Cook everything at 85ºC. Cool the cream and when it reaches 40ºC add the first amount of butter. Cover with cling film in contact and leave in the refrigerator for 24 hours. Place the cream in the food processor with the whisk. Mix the remaining butter with the hazelnut paste. Gradually add the cream. Place the cream on the sablé biscuit. 

Heat the cream with the sugar. Pour over the egg yolks and cook everything at 85ºC. Add in two stages over the melted couverture and emulsify. Cover with cling film in contact and store for 24 hours in the refrigerator. Measure out onto the sponge cake using a piping bag.