In mixing bowl, stir the flour, sugar and salt together. Toss cubed butter and shortening in the flour mixture.
In medium saucepan, melt brown sugar and butter together. Bring the mixture to a simmer and stir for one minute.
Remove the caramel from the heat and add vanilla and salt. Be careful, as the vanilla will sputter a bit when it is added. Stir and set aside.
Spread apple mixture over pastry. Pour caramel sauce over apples and cover with streusel.