Preheat oven to 180 C / Gas 4. Reserve 150g of preserved apples and set aside.
Spoon remaining preserved apples over biscuit base. In a large bowl, combine cream cheese, sugar and vanilla. Beat until smooth then add eggs and mix well. Pour over apple filling in base.
Bake at 180 C / Gas 4 for 35 minutes, or until centre is set. Remove from oven and cool to room temperature.
Mix reserved preserved apples and toffee sauce in a small saucepan. Heat for about 1 minute. Arrange apple slices around outside edge of cheesecake. Spread caramel sauce evenly over. Decorate with pecan halves around edge. Sprinkle with chopped pecans. Chill until ready to serve.