Cream the butter. Gradually add the sugar.
Work the mixture for a long time so that it is frothy.
Add the walnuts.
Prepare a custard. Let it cool, then mix these two preparations.
Line the bottom and edges of a
charlotte mould. Place the cookies in the rounded part against the mold.
Spoon the nut mixture in the center of the cookies.
Also cover with biscuits (flat part outside, this time)
and refrigerate overnight.
Unmold and glaze with chocolate before serving. For this:
melt the chocolate with the water and the butter, in a bain-marie. Stir when the chocolate is soft. On
gets a smooth, shiny cream.
Pour it in the center of the charlotte and leave the chocolate
topping the edges by simply tilting the cake.
Source:Les Bons Desserts