Preheat oven to 350°.
To prepare crust, lightly spoon flour into a dry measuring cup; level with a knife. Place flour, pecans, and salt in a food processor; process until pecans are finely ground. Add butter; pulse 4 times or until mixture resembles coarse meal.
With processor on, slowly add 2 tablespoons syrup through food chute, processing just until combined (do not form a ball). Place dough on a lightly floured surface; knead lightly 4 or 5 times (dough will be sticky).
Place dough in a 9-inch round removable-bottom tart pan lightly coated with cooking spray. Place a sheet of plastic wrap over dough; press dough into bottom and up sides of pan. Discard plastic wrap. Pierce bottom and sides of dough with a fork; bake at 350° for 15 minutes or until lightly browned. Cool on a wire rack.
To prepare filling, combine 1/2 cup syrup and cornstarch. Place syrup mixture, sweet potato, and next 6 ingredients (sweet potato through nutmeg) in a food processor; process until smooth, scraping sides. Spoon mixture into prepared crust, spreading evenly. Bake at 350° for 50 minutes or until set. Cool on a wire rack.
Place 1/2 cup syrup in a heavy saucepan; bring to a boil. Cook until reduced to 1/3 cup; remove from heat. Cool and drizzle about 1 1/2 teaspoons over each serving.