HEAT oven to 350°F. Line 8 x 8-inch baking pan with foil, extending foil over edge of pan. Coat with no-stick cooking spray.
STIR cookie mix and 1/2 cup melted butter in medium bowl with fork until evenly moistened. Press into bottom of prepared pan. Bake 10 minutes.
WHISK egg in medium bowl. Whisk in corn syrup, 2 tablespoons melted butter and vanilla until blended. Stir in pecans. Spread evenly over partially baked layer.
BAKE 23 to 25 minutes or until topping is set and golden brown. Cool 15 minutes. Remove from pan using edges of foil. Place on cutting board. Pull foil away from sides of bars. Cool completely. Trim outer edge before cutting into bars.