Whisk Karo Syrup, eggs, white sugar, cooled melted butter and vanilla extract together in a large mixing bowl.
Add the pecans and stir with a spoon to coat all of pecans.
Pour the pecan filling into the par baked pie crust.
Bake for approximately one hour.
If the crust begins to brown too quickly cover edges with foil or silicone crust protector.
To test if pie is done, remove the pie from the oven and shake it slightly. The pie is done when the center of the pie is a little jiggly. The center will firm up as the pie cools.
Allow pie to cool for at least two hours before serving.