Preheat your oven to 350°F (175°C). This step is crucial as it ensures that your bars bake evenly. While the oven is heating, grab your 9x13-inch baking pan and grease it well with butter to prevent sticking.
Prepare the crust by combining the all-purpose flour, salted butter, and brown sugar in a mixing bowl. Use a pastry cutter or your fingers to mix until it resembles coarse crumbs. Press this mixture evenly into the bottom of your greased pan and bake for 12 to 15 minutes, or until the crust is lightly golden brown.
While the crust is baking, start on the filling. In a large mixing bowl, beat the eggs lightly. Then add the light corn syrup, granulated sugar, melted butter, and vanilla extract to the eggs. Whisk everything together until well combined. Make sure there are no lumps!
Stir in the chocolate and chopped pecans to the egg mixture. This is where the magic happens! Mix gently to ensure the chocolate and nuts are evenly distributed throughout the filling.
Once the crust is done, remove it from the oven. Pour the filling mixture evenly over the warm crust, spreading it out with a spatula if necessary.
Bake the bars for an additional 25 to 30 minutes, or until the filling is set and a toothpick inserted in the center comes out clean.
Remove the bars from the oven and let them cool in the pan on a wire rack. This cooling process will help them firm up. Once cool, slice them into squares or bars, whichever you prefer.
Storage tip: If any bars remain (though I doubt they will!), store them in an airtight container at room temperature. For those in warmer climates, refrigerating them can help keep them fresh.