Preheat your oven to 350°F (175°C). In a mixing bowl, combine cold butter, brown sugar, and all-purpose flour. Use a pastry cutter or your fingers to blend until the mixture resembles coarse crumbs. Press this mixture firmly into the bottom of a lined 9x9-inch baking pan, ensuring an even layer across the base.

Place the prepared crust in the preheated oven and bake for 15–20 minutes, or until it turns lightly golden and firm to the touch. Keep an eye on it, as you want a golden hue without burning. Once baked, remove the crust from the oven and set it aside to cool slightly while you prepare the caramel layer.

Pour your caramel sauce evenly over the warm crust, ensuring that each corner gets covered. Sprinkle the chopped pecans generously over the caramel layer, distributing them evenly for a delightful crunch in every bite.

Return the assembled bars to the oven for an additional 10 minutes. You'll know they're ready when the caramel layer is bubbly and hot, providing a glossy finish on top. Once baked, carefully remove the bars from the oven and allow them to cool for a few minutes before adding the chocolate topping.

While the bars are still warm, sprinkle the chocolate chips evenly over the top. Let them sit for a minute to soften, and then use a spatula to spread the melted chocolate into a smooth, even layer.

Allow the turtle bars to cool at room temperature for at least 1 hour, or until fully set. For quicker results, you can refrigerate them for about 30 minutes. Once cool, slice the bars into squares for serving, revealing the delicious layers inside.