Preheat oven to 350°. Line a 15- x 10-inch jelly-roll pan with aluminum foil; lightly grease foil. Beat butter and 1/2 cup sugar at medium speed with a heavy-duty electric stand mixer until well blended. Add egg yolks, and beat until combined. Gradually add flour, beating at low speed 1 to 2 minutes or just until combined. Press mixture onto bottom of prepared pan.
Bake at 350° for 15 to 20 minutes or until golden brown. Remove from oven, and spread preserves over crust. Sprinkle with chocolate morsels.
Beat egg whites and salt at high speed, using whisk attachment, until foamy. Gradually add remaining 1 cup sugar, 1 Tbsp. at a time, beating until glossy and stiff peaks form. Fold in pecans. Gently spread egg white mixture over chocolate mixture.
Bake at 350° for 30 to 35 minutes or until meringue is browned and crispy. Cool completely on a wire rack (1 hour). Cut into bars.
Note: We tested with Dickinson's Pure Seedless Cascade Mountain Red Raspberry Preserves.