Beat butter, 1/3 cup powdered sugar and vanilla in large bowl with mixer until well blended. Gradually beat in 1-1/2 cups flour. Stir in nuts; press onto bottom of13x9-inch pan sprayed with cooking spray. Bake 15 min.
Meanwhile, beat cream cheese and granulated sugar in medium bowl with mixer until well blended. Add eggs, 1 at a time, beating well after each addition. Add remaining flour, lemon zest and juice; mix well.
Pour cream cheese mixture over crust. Bake 30 min. or until center is set. Cool completely. Sprinkle with 1 Tbsp. powdered sugar just before cutting into bars to serve.