Preheat oven to 350˚. Spread pecan halfs onto a baking sheet, and bake for 5 minutes. Remove from oven, stir pecans around baking sheet, and place back into oven for another 5 minutes.

Bring brown sugar, whipping cream, butter, and corn syrup to a boil in a heavy 4-qt. saucepan over medium heat, stirring constantly. Boil, stirring occasionally, 4 to 6 minutes or until a candy thermometer registers 236˚F (soft ball stage). Remove sugar mixture from heat.Let sugar mixture stand until candy thermometer reaches 150˚F (20 to 25 minutes). Stir in pecans and vanilla using a wooden spoon; stir constantly 1 to 2 minutes or just until mixture begins to lose its gloss.

Let sugar mixture stand until candy thermometer reaches 150˚F (20 to 25 minutes). Stir in pecans and vanilla using a wooden spoon; stir constantly 1 to 2 minutes or just until mixture begins to lose its gloss.

Quickly drop by heaping tablespoonfuls onto wax paper, and let stand until firm (10 to 15 minutes).