In a food processor, grind the almonds to a powder by pulsing off and on to keep the powder loose. Mix the almonds with the powdered sugar and flour. In a separate bowl, beat the egg whites to soft peaks. Gradually beat in the granulated sugar until stiff. Fold in the lemon zest and almond extract. Pipe the mixture with a pastry bag using a round 1/4-inch tip into 1 1/2-inch rounds onto baking sheets lined with lightly buttered waxed paper or parchment. Bake in a preheated 275 degree oven for 1 hour, checking to make sure the amaretti don't brown. Turn off the oven and let the amaretti dry out for an additional hour--they should be very crisp. Store them in an airtight container in the refrigerator or freezer. : About 24 cookies COOKING RIGHT SHOW #CR9633 ----