Empty jar of cookie mix into large mixing bowl. Use your hands to thoroughly blend mix.
Add 1 stick (1/2 cup) butter or margarine, melted, 1 egg, slightly beaten, and 1 teaspoon vanilla extract. Mix until completely blended. You may need to finish mixing with your hands. Shape into balls the size of walnuts. Place 2 inches apart on sprayed baking sheets. Bake at 350 degrees F for 11 to 13 minutes until edges are lightly browned.
Cool 5 minutes on baking sheet. Remove cookies to racks to finish cooling.
Makes about 30 cookies.