PREHEAT oven to 350° F.
BEAT flour, sugar and butter in large mixer bowl until mixture resembles fine crumbs. Press onto bottom of ungreased 13 x 9-inch baking pan. Place pecans evenly over unbaked crust.
COMBINE butter and sugar in medium saucepan. Cook over medium heat, stirring constantly, until mixture begins to boil. Boil, stirring constantly, for 1 minute. Pour evenly over pecans.
BAKE for 18 to 22 minutes or until bubbly. Sprinkle with morsels; let stand for 2 to 3 minutes or until morsels are shiny. Swirl morsels, leaving some whole for marbled effect. Cool completely in pan on wire rack; cut into bars. Store in an airtight container.