Beat eggs in a large mixing bowl at high speed of electric mixer for 8 minutes. Gradually add sugar, beating well. Combine flour, cream of tartar, soda, and salt in a small mixing bowl; stir well. Gradually add flour mixture to egg mixture, beating until smooth. Stir in lemon juice, vanilla, apple, and 1 cup pecans.
Pour batter into a lightly greased 13- x 9- x 2-inch baking pan. Bake at 325° for 35 minutes. (Torte will rise, then fall.) Remove from oven, and cool completely. Cut into 3 - inch squares. Transfer to individual serving plates; serve with a dollop of whipped cream and additional chopped pecans.