1Heat oven to 350°F. Line cookie sheet with cooking parchment paper.
2In large bowl, mix butter, brown sugar, granulated sugar and vanilla. Stir in flour, baking soda and salt. Gently stir in oats and cereal. On cookie sheet, press dough into 12x10-inch rectangle, about 1/4 inch thick. (Dough will be crumbly at first.)
3Bake 20 minutes or until firm and golden brown. Cool 10 minutes; remove to cooling rack with parchment paper still attached. Cool completely, about 20 minutes. Break cookie into irregular pieces. Dip in melted chocolate.