Gather the ingredients. Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 10x15-inch jellyroll pan.
Combine flour, ½ cup sugar, and salt in a large bowl. Cut in 1 cup of butter until mixture resembles coarse crumbs. Sprinkle mixture evenly over the prepared pan and press in firmly to make a crust. Bake in the preheated oven for 20 minutes.
Meanwhile, mix corn syrup, 1 ½ cups sugar, eggs, 3 tablespoons melted butter, and vanilla together in a large bowl until smooth. Stir in chopped pecans; spread filling evenly over baked crust as soon as it comes out of the oven.
Bake in the preheated oven until filling is set, about 25 minutes. Allow to cool completely in the pan on a wire rack before slicing into bars.
