Leave the eggs for 1 hour at room temperature and separate the whites from the yolks. Mix the egg whites with the sugar, stir without beating them and heat in a water bath for 10 min. while stirring nonstop.
The sugar will dissolve and the egg whites will turn a matt white. Take the container off the stove and beat the mixture until it cools and becomes smooth and shiny.
Add the flour and vanilla and stir carefully.
Grind the walnuts and add them to the mixture. Grate the chocolate and add it as well, stirring very carefully. Put teaspoonfuls of the mixture in a tray covered with baking paper, leaving 2 between the meringues.
Bake 20 min. at 338°F (170 °C). Leave them to cool in the oven with the door open. Once fully cooled, take them out and put them in a plastic container. They will be even more delicious if you wait till the next day.