How to Make It
Preheat oven to 350°F. Stack piecrusts on top of each other on a lightly floured work surface, and roll into 1 thick (12-inch-wide) piecrust. Fit piecrust inside a 9-inch pie dish. Line with parchment paper, and fill with pie weights.
Bake in preheated oven until edges are set, about 15 minutes. Remove parchment paper and pie weights. Continue baking until bottom of crust is set, about 5 minutes. Remove from oven; let cool completely, about 30 minutes.
Meanwhile, cook 1 cup of the packed brown sugar and 1/2 cup butter in a large skillet over medium, stirring occasionally, until butter melts. Stir in apples; cook, stirring occasionally, until apples are very tender, about 20 minutes. Remove from heat. Remove apples from sauce using a slotted spoon, and set aside; reserve sauce in skillet for serving.
Stir together pumpkin, granulated sugar, pumpkin pie spice, and 1 of the eggs in a bowl until smooth. Spread evenly into bottom of cooled piecrust.
Stir together corn syrup, 3 tablespoons melted butter, vanilla, and remaining 1/3 cup packed brown sugar and 2 eggs in a bowl until smooth. Stir in pecans. Pour over pumpkin filling. Spoon cooked apples over mixture.
Loosely cover crust edges with aluminum foil. Bake at 350°F 30 minutes. Remove foil; continue baking until center is just set, 10 to 15 minutes. Remove from oven; let cool completely on a wire rack, about 2 hours. Refrigerate until just chilled, about 1 hour.
Microwave reserved apple sauce in a small microwavable bowl on MEDIUM (50% power) until warmed, about 1 minute; stir until smooth. Serve warm sauce alongside pie. If desired, top with whipped cream.