Preheat your oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving a 2-inch overhang on the long sides. This will help you lift the bars out easily after baking.

In a medium bowl, whisk together the flour and granulated sugar. Add the cold, cubed butter. Cut the butter into the flour mixture using a pastry blender or your fingers until it resembles coarse, damp sand.

Press the crust mixture firmly and evenly into the bottom of the prepared pan. Bake for 20 minutes until the edges are just beginning to turn a light golden brown.

While the crust is baking, prepare the filling. In a large bowl, whisk together the packed light brown sugar, light corn syrup, melted butter, lightly beaten eggs, and vanilla extract until everything is smooth and fully combined.

Gently stir in the pecan halves until they are evenly coated with the filling mixture.

Once the crust is pre-baked, remove it from the oven and pour the pecan filling evenly over the top. Spread gently to ensure an even layer. Return the pan to the oven and bake for an additional 30-35 minutes.

The Pecan Pie Bars are done when the center is set (it should not wobble excessively) and the top is a deep golden brown. The filling will puff up while baking and settle as it cools.

Remove the pan from the oven and place it on a wire rack to cool completely. This can take at least 2 hours. For best results and the cleanest cuts, chill the bars in the refrigerator for 1-2 hours before slicing.

Once cooled and chilled, use the parchment paper overhang to lift the bars out of the pan. Place on a cutting board and slice into 24 bars. Serve at room temperature or slightly chilled.