Heat oven to 350. In large mixer bowl, combine flour, sugar, butter, egg yolk and almond extract. Beat at low speed, scraping bowl often, until particles are fine, 2-3 minutes. Press on bottom of greased 15x10x1-inch jelly-roll pan. In small bowl, beat egg white and water until frothy; brush on dough. Sprinkle nuts over top. Bake for 15 to 20 minutes, or until very lightly browned. Cool completely. Cut into bars.Makes about 2 1/2 dozen bars.