Cream butter; gradually add sugar, beating well. Add egg yolk; mix well.
Combine flour, salt, and cinnamon; add to creamed mixture alternately with bourbon, beginning and ending with flour mixture. Stir in vanilla. (Batter will be thick.)
Press dough evenly in a greased 13- x 9- x 2-inch baking pan. Brush with egg white, and sprinkle with chopped nuts. Bake at 350° for 45 minutes or until lightly browned. Cool in pan 5 minutes; cut into bars.