Pecan Toffee

Line a 15-inch x 10-inch baking dish with strong aluminum foil; lightly grease the foil. Sprinkle 1 cup of pecans to within 1 inch of the edges.Bring the sugar, butter, and 1/3 cup water to a boil in a heavy saucepan over medium-high heat, stirring constantly. Cook over medium-high heat, stirring constantly, for 12 minutes or until the candy thermometer reads 310 ° (hard cracking stage). Sprinkle with pecans; sprinkle with chocolate chips. Let stand for 30 seconds.Sprinkle with the remaining 1/2 cup pecans. Chill for 30 minutes. Mash the butterscotch with a hammer or rolling pin. Store in an airtight container.