Preheat oven to 350°F. Grease a 13x9x2-inch baking pan or line it with foil and spray the foil with nonstick cooking spray (optional); set pan aside.

In a large bowl, combine 2 cups all-purpose flour and 1 cup packed light brown sugar. Using a pastry blender or fork, cut in 1/2 cup (1 stick) butter until the mixture forms fine crumbs (a few larger crumbs may remain).

Press the crumb mixture evenly into the bottom of the prepared pan to form the crust.

Sprinkle 1 cup pecan halves evenly over the crust.

Make the toffee topping: in a small saucepan combine 2/3 cup butter and 1/3 cup packed light brown sugar. Cook over medium heat, stirring constantly, until the mixture comes to a boil. Once boiling, continue to boil while stirring constantly for 30 seconds. Remove from heat and use immediately.

Drizzle the hot toffee topping evenly over the pecans and crust.

Bake at 350°F for 20 to 22 minutes, or until the topping is bubbly and golden.

Remove the pan from the oven and immediately sprinkle 1 cup Hershey’s Milk Chocolate Chips evenly over the hot topping. Press the chocolate chips gently into the topping so they begin to melt and adhere.

Cool completely in the pan on a wire rack. Once cooled, cut into bars (about 36).