One 23 cm unbaked pie shell. Put chopped apples in a large bowl. Separate egg yolk and egg white into two small mixing bowls. Beat egg yolk and mix well with sugar, flour, vanilla, lemon juice and pecans; add to chopped apples. Beat egg white until foamy; add to apple mixture. Stir well and pour mixture into unbaked pie shell. Bake at 350 degrees 30-45 minutes or until apples are tender and brown.