We fry the walnut a little, in the oven, then we break it with the rolling pin; mix the walnuts with the flour.
Whisk the egg whites, with a pinch of salt, in a bain marie; gradually add the sugar and mix until you get a shiny, firm meringue. Incorporate vanilla and walnut mixed with flour, lightly, using a wooden spoon.
Divide the composition in two and bake two sheets, on the back of the tray, in the preheated oven, at 180 degrees, until the sheets start to brown on the edges.
For the cream mix the yolks with 100 g powdered sugar, also in a bain marie; we also add the ness. Let cool.
Mix the butter with 100 g of powdered sugar and then incorporate, spoon by spoon, cold cream.
Divide the cream in half and fill the sheets.
It's better the next day.