PREHEAT oven to 350°F. Line 13 x 9-inch baking pan with foil; lightly grease. FOR PRETZEL CRUST: COMBINE melted butter, pretzels and ¼ cup brown sugar in medium bowl. Press mixture onto bottom of prepared baking pan. BAKE for 5 minutes. Let cool for 5 minutes. FOR COOKIE DOUGH: COMBINE flour, baking soda and salt in small bowl. Beat butter, brown sugar and granulated sugar in large mixer bowl until creamy. Add eggs and vanilla extract; beat until just blended. Gradually beat in flour mixture. Stir in 1¼ cups DelightFulls morsels. DROP small spoonfuls of cookie dough onto pretzel crust and spread evenly. Sprinkle with remaining ¼ cup DelightFulls morsels. BAKE for 28 to 30 minutes or until top is golden brown. Cool completely in pan on wire rack. Lift out by foil edges to cutting board. Carefully remove foil. Cut into bars. Store in airtight container.