Preheat oven to 350 degrees F.
In a heavy 2-to 3-quart saucepan placed over medium heat, combine dark brown sugar, corn syrup and butter. Bring to a boil, stirring constantly. Reduce heat and boil gently for 5 minutes, stirring occasionally. Remove pan from heat, stir in vanilla and let cool 10 minutes.
In a small bowl, slightly beat eggs. Stirring constantly, pour eggs into sugar syrup slowly until mixture is well blended. Stir in pecans. Pour into pie crust and bake 35 minutes or until pie sets. Cool on wire rack