Separate yolks from egg whites, add a few drops of lemon juice and beat them. Then add the sugar, starch and ground hazelnuts. All poured into pan and bake 20-25 minutes at 120 C. When the base is baked is cut to two to cool. Boil coffee and sugar to dissolve it. Yolks are broken down in a water bath and when they start to thicken add the coffee and sugar. Reduce the heat and add and the butter, which should not be melted and be ingested by the egg mixture. When the mixture is homogeneous, is removed from the heat. When lightly tighten and become more rigid pour into spray and make a rectangle of cream on the base. Cream mix with a mixer. Then fills the rectangle formed by cream with whipped cream and put second base. Garnish it with the rest of the cream and put the cake in the refrigerator to harden. Finally optional garnish with nuts on top.