Beat egg whites until frothy; add sugar gradually, beating constantly until stiff peaks are formed.
Sprinkle hazelnuts over the egg whites and gently fold together just until blended.
Drop mixture by teaspoonfuls onto lightly greased cookie sheets.
If necessary, work over each portion with the back of a spoon to round it.
Bake at 300Â°F about 25 minutes.
With a spatula, carefully remove cookies from cookie sheets to wire racks.