Put the egg whites in a stainless steel bowl (it seems to beat faster) with a pinch of salt and beat vigorously with the mixer, then add the sugar, butter, chopped hazelnuts and finally the flour. All this will mix everything. with the mixer but at low speed.
The oven is heated to 180 degrees and when they are all mixed, with a teaspoon we take from the bowl and put in the stove tray on baking paper piles at distances of 3 cm. Put the tray in the oven at 180 degrees and leave it until golden brown and then leave it at 120 degrees until it hardens. A stove tray will come out of this amount.