CRUST:

2 c. all-purpose flour
1 c. brown sugar, firmly packed
1/2 c. butter, softened
1 can pecan halves

CARAMEL LAYER:

2/3 c. butter
1/2 c. brown sugar, firmly packed
1 c. semi-sweet chocolate chips

Heat oven to 350 degrees. In large mixer bowl combine all crust ingredients except pecans. Beat at medium speed, scraping bowl often, until well mixed and particles are fine (2 to 3 minutes). Press on bottom of 13 x 9 inch baking pan. Sprinkle pecans evenly over unbaked crust. In 1 quart saucepan combine 2/3 cup butter and 1/2 cup brown sugar. Cook over medium heat, stirring constantly, until mixture comes to a full boil. Boil, stirring constantly, until small amount of mixture dropped into ice water forms a firm ball or candy thermometer reaches 242 degrees (about 1 minute). Pour evenly over pecans and crust. Bake for 18 to 22 minutes or until entire caramel layer is bubbly. Remove from oven. Immediately sprinkle with chips; allow to melt slightly (2 to 3 minutes). Swirl chips leaving some whole for a marbled effect. Cool completely; cut into bars.