Preheat oven to 350 degrees. Empty contents of jar into mixing bowl and thoroughly blend. Add butter, egg and, vanilla; mix until completely blended. It will be stiff. Shape into 1 inch balls. Place 2 inches apart on greased baking sheets. Bake in preheated oven 13 to 15 minutes until edges are lightly browned. Cool 5 minutes on baking sheet.