Grind the almonds through the finest blade of a food processor. Grind twice again. Mix in the powdered sugar. Blend in the egg whites and almond extract.
Form into a ball. Place in a tightly covered container and refrigerate for at least 4 days to age.
Makes 1 pound almond paste.
Preheat oven to 325° F.
Soften the almond paste with your hands and work in the sugar, salt, flour, powdered sugar and egg whites.
Drop by teaspoonfuls 2-inches apart onto baking sheets lined with parchment baking paper. Pat the tops lightly with fingers dipped in cold water. Bake for 18 to 20 minutes, or until set and delicately browned. Remove from the paper and cool on wire racks.Servings: 5 dozen cookies