This is a wonderful combination of cookie and candy, with the crumbly crust serving as counterpoint to the chewy caramel topping. For a nice presentation, place the cookies in paper candy cups, and set the cups in a basket; wrap clear cellophane around the basket, tie it up with raffia and decorate it with pine cones. Save the irregularly shaped leftover cookies to enjoy as a snack. From Bon Appétit.
Preheat oven to 350°F.
Line 13x9x2-inch baking pan with foil, leaving 1-inch overhang on all sides.
Butter foil.
Blend flour, powdered sugar, cornstarch and salt in processor.
Add butter and process until mixture begins to clump together.
Press dough evenly onto bottom of foil-lined pan.
Bake crust until set and light golden, about 25 minutes.
Remove from oven.
Let stand while preparing topping.
Reduce oven temperature to 325°F.
Stir brown sugar, corn syrup and butter in heavy medium saucepan over medium-high heat until sugar dissolves and mixture boils; boil 1 minute.
Add pecans and cream; boil until mixture thickens slightly, about 3 minutes.
Stir in vanilla.
Pour hot topping over warm crust.
Bake nut-topped crust until caramel is darker and bubbles thickly, about 20 minutes.
Transfer pan to rack.
Cool completely in pan (topping will harden).
Lift foil out of pan onto cutting board.
Using heavy sharp knife, cut crust with nut topping into 1 1/2x1-inch diamonds.
Can be made 1 week ahead. Store between sheets of waxed paper in airtight container at room temperature.
