Preheat the oven to 375° F. Prepare pastry; set aside in refrigerator until ready to use.
In a small saucepan, stir 3/4 cup of the brown sugar with the half-and-half over medium heat until the sugar dissolves. Remove from heat and add the butter and vanilla, stirring until butter melts. Set mixture aside to cool completely.
In a medium bowl, toss the prepared apples with the lemon juice. Add the remaining 1/4 cup brown sugar, cornstarch, lemon zest, orange zest (if using), cinnamon, allspice and nutmeg. Toss to combine well.
Sprinkle 1 tsp flour onto the bottom of the unbaked pie shell. Turn apple mixture onto the sprinkled flour. Pour the cooled butterscotch mixture evenly over the apples.
Cover with top crust; trim overhang to 1-inch from edge, seal and flute. Make several slits in top crust to allow steam to escape.
Bake for about 45 minutes or until golden brown and the juices are bubbling (look into the slits to check). Cool completely on a wire rack before serving.Makes 8