To make the crust: Combine flour, brown sugar, and butter, beating at medium speed with an electric mixer until the mixture resembles fine crumbs.

Press onto bottom of ungreased 9x13 baking pan. Place pecans evenly over top of crust.

To make the topping: Preheat oven to 350°. Combine butter and brown sugar in 1-quart saucepan. Cook over medium heat, stirring constantly, until mixture begins to boil. Continue stirring and allow mixture to boil for 1 minute. Pour evenly over crust and pecans.

Bake 18-22 minutes, until caramel layer is bubbly. Be sure not to overbake.

Remove from oven. Sprinkle with chocolate chips and allow to melt slightly. Swirl chocolate chips over the crust. Cool completely before cutting into bars.