Preheat oven to 325 degrees F (165 degrees C).

Spray a 13x9 inch baking pan with non-stick cooking spray.

In a mixing bowl, combine flour, sugar, and softened butter.

Mix until the mixture is crumbly.

Press the crumbly mixture evenly onto the bottom of the prepared baking pan to form the crust.

Bake the crust at 325 degrees F (165 degrees C) for 15 minutes.

While the crust is baking, prepare the toffee layer.

In another mixing bowl, combine sweetened condensed milk, egg, vanilla extract, and chopped pecans.

Stir well to mix all ingredients together.

Once the crust is baked, remove it from the oven.

Spread the toffee mixture evenly over the baked crust, ensuring the entire surface is covered.

Return the pan to the oven and bake for an additional 25-30 minutes, or until the toffee layer is bubbly and golden brown.

Remove the baked bars from the oven and immediately sprinkle with semi-sweet chocolate chips.

Let the chocolate chips melt slightly from the heat of the bars.

Once the chocolate chips are softened, spread them evenly over the toffee layer.

Allow the pecan toffee bars to cool completely in the pan.

Once cooled, cut the bars into squares or rectangles.

Serve and enjoy!