1. In small bowl stir together KEEBLER SANDIES Pecan Shortbread cookies, flour and 2 tablespoons of the butter. Press onto bottom of ungreased 11 x 7 x 1 1/2-inch baking pan. Bake at 350°F for 10 minutes.
2. For filling, in medium bowl stir together eggs, brown sugar, corn syrup, the remaining 2 tablespoons butter and vanilla. Stir in pecans and chocolate morsels. Evenly spread over hot crust. Bake at 350°F about 20 minutes more or until filling is set. Cool completely in pan on wire rack. Cut into twenty-four bars.