Prepare the Crust : Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish and line it with parchment paper for easy removal. In a medium bowl, combine the unbleached flour, melted butter, and 1/2 cup packed brown sugar. Stir until a dough forms. Press the mixture evenly into the bottom of the prepared baking dish to create the crust. Bake for 15 minutes or until lightly golden. Remove from the oven and set aside to cool slightly.

Make the Filling : In a large mixing bowl, whisk together the beaten eggs, melted butter, remaining 1/2 cup brown sugar, and Karo light corn syrup. Stir until well combined. Fold in the chopped pecans and 2 cups of shredded coconut, mixing gently to distribute evenly.

Assemble and Bake : Pour the filling mixture over the pre-baked crust, spreading it evenly with a spatula. Sprinkle the remaining 1/2 cup of shredded coconut evenly over the top for added texture and flavor. Return the dish to the oven and bake for 25-30 minutes, or until the filling is set and golden brown on top.

Cool and Serve : Remove the pan from the oven and let the bars cool completely in the baking dish. For best results, refrigerate for at least 1 hour before slicing. Once chilled, use the parchment paper to lift the bars out of the pan. Cut into squares or rectangles and serve.