Preheat oven to 350 degrees.
Start off with the crust: Mix together the flour, butter and sugar at medium speed with a hand mixer. When the mixture looks like crumbs, add in the chopped pecans.
Add the mixture to the bottom of a greased 9x13 pan.
Bake the crust for 20 minutes.
While the crust is baking, mix together the corn syrup, brown sugar, eggs, flour, and vanilla until it's completely mixed.
Add in the chopped pecans and fold in.
Add the filling on top of the baked crust, making sure to spread it evenly.
Bake for another 30 minutes until filling is set.
Remove from the oven, and let cool completely.
Serve & enjoy!