Let pie crust stand at room temperature according to package directions. Preheat oven to 400 degrees F. Line a 10- to 10 1/2-inch tart pan with removable bottom with pie crust, pressing into bottom and up sides. Line the unpricked pastry shell with a double thickness of heavy-duty foil. Bake for 5 minutes. Remove foil. Bake for 5 to 7 minutes more or until pastry is nearly done. Remove from the oven.
Meanwhile, in a large skillet cook sausage and onion until meat is browned and onion is tender, stirring frequently. Drain fat. Stir in pie filling and 2 tablespoons brown sugar. Transfer mixture to partially baked pie shell.
In a medium bowl cut butter into 1/3 cup brown sugar until crumbly. Stir in oats and pecans; sprinkle evenly atop sausage mixture.
Bake, uncovered, for 30 to 35 minutes or until top is golden. Remove from oven; drizzle with maple syrup. Let stand 15 minutes. Remove sides of pan and slice to serve.