Pumpkin Pie with Pecan-Caramel Topping

Prepare Crust : In food processor with knife blade attached, blend toasted pecans and sugar until finely ground. Add flour and salt to nut mixture and pulse to blend. Add margarine with shortening, and pulse just until mixture resembles very coarse crumbs. With processor running, add 3 tablespoons ice water, stopping just before dough forms a ball. Shape dough into a disk.

Preheat oven to 400 degrees F. Between lightly floured sheets of waxed paper, with rolling pin, roll dough into a round 1 1/2 inches larger in diameter than inverted 9-inch pie plate. Dough will be very tender; refrigerate if too soft to roll. Gently ease dough into pie plate, trim edge, leaving 1-inch overhang. Fold overhang under, bring up over pie-plate rim and pinch to form high decorative edge. With fork, prick bottom and side of pie shell at 1-inch intervals to prevent puffing and shrinking during baking. Refrigerate pie shell about 30 minutes.

Line pie shell with foil and fill with pie weights, dried beans, or uncooked rice. Bake pie shell 20 minutes, remove foil with weights and bake 10 minutes longer or until lightly browned. Cool pie shell on wire rack at least 15 minutes. Turn oven control to 350 degrees F.

Prepare Pumpkin Filling : In large bowl, with wire whisk, beat pumpkin and remaining filling ingredients.

Pour filling into cooled pie shell. Bake pie 50 to 60 minutes, until knife inserted 1 inch from edge of pie comes out clean. Transfer pie to wire rack until it cools and becomes slightly firm, about 1 hour.

Prepare Pecan-Caramel Topping : In 2-quart saucepan, heat brown sugar, cream, corn syrup, margarine or butter, and vinegar to boiling over high heat, stirring occasionally. (Do not use smaller pan, mixture bubbles up during cooking.) Reduce heat to low, simmer, uncovered, 5 minutes, stirring frequently. Remove saucepan from heat, stir in pecans and vanilla. (Topping will be very thin when hot but will thicken as it cools.) Pour hot topping over cooled pie. Refrigerate pie at least 4 hours or overnight.