Homemade Filo Dough
Sift the flour and salt into a deep mixing bowl. Beating constantly with a large spoon, pour in the water in a thin, slow stream and beat until the flour and water are well-blended. Then knead the dough in the bowl by pressing in down, pushing it forward several times with the heel of your hand and folding it back on itself. Repeat 5-20 minutes, or until the dough can be gathered into a soft, somewhat sticky ball.
Add the olive oil, 1 tablespoon at a time, kneading well after each addition and continue kneading for about 25 minutes longer, or until the dough is smooth and satiny. Cover the bowl with plastic wrap and let the dough rest at room temperature for at least 2 hours. (Tightly covered, the dough can be kept at room temperature for overnight or for about 12 hours, or in the refrigerator for a week or so. If refrigerated, it should be brought to room temperature before it is rolled).
When you are ready to roll and use the dough, divide it into 20 equal portions and shape each piece into a ball about 1 1/2 inches in diameter. Sprinkle a smoothly woven kitchen towel with a little cornstarch and, one at a time, roll each ball with a rolling pin into a round about 7 inches in diameter. As they are rolled, place the rounds between strips of wax paper and stack them on a plate. Then cover all the rounds with a kitchen towel and let them rest for about 30 minutes.
To shape each sheet of filo, stretch it over the backs of your hands by lifting the dough and pulling your hands apart repeatedly until the filo is paper-thin. Working quickly but gently, you should be able to form a sheet about 14 inches wide by 18 inches long. Trim off the thick edges to make a 12x16-inch rectangle.
Freshly-made filo dries our quickly, so it should be buttered or shaped as described in the recipe you are following before you proceed to roll and stretch the next sheet. A home baker cannot make filo as thin as the commercial product; therefore, use only half as many layers as called for in the recipe, and cut the rectangle in half instead of folding it.