Combine the almonds, hazelnuts, and sugar in the bowl of a food processor fitted with the metal blade and pulse repeatedly to grind to a fine powder. Pour into a medium bowl and stir in the flour. In a clean, dry bowl, whip the egg whites with the salt and continue whipping until they hold a soft peak. Stir the egg whites into the nut mixture. They will fall, but it does not matter, since the tegole will leaven slightly while they are baking.
Butter 4 or 5 jelly roll pans or cookie sheets thickly. For this purpose it is better to use very soft (but not melted) butter, applying it with a brush. Place twelve
Immediately upon removing the pan from the oven, pry the tegole off the pan with a flat, sharp-edged spatula and drape them over a rolling pin or a roll of aluminum foil so that they curve and become crisp. Repeat with the remaining batter. Remove the tegole from the rolling pin or roll of foil after they have cooled enough to hold their shape, and finish cooling on a rack.
Store the tegole airtight or they will absorb humidity and become soggy.
© 1990 Nick Malgieri. All rights reserved.