In a large bowl,toss apples with lemon juice and vanilla. Combine the pecans, sugars, cinnamon and cornstarch, add apple mixture and toss to coat.

Pour caramel topping over the bottom of the pastry shell, top with apple mixture (shell will be full). Drizzle with butter

In a small bowl, combine the flour, pecans and sugar. Cut in butter until mixture resembles coarse crumbs. Sprinkle over filling

Bake at 350 for 55-65 minutes or until filling is bubbly and topping is browned. Immediately drizzle with caramel topping. Cool on wire rack