Preheat over to 350 degrees F. Grease 2 large cookie sheets.
Prepare Cookie Dough. In a large bowl, with spoon, mix all dough ingredients until smooth.
Drop dough by heaping tablespoons, 2 inches apart, on each prepared cookie sheet.
Bake 14 minutes until puffy - test by inserting a toothpick in the center, it is done if the toothpick comes out clean. Transfer cookies to wire racks to cool completely.
While cookies are baking, prepare Marshmallow Creme Filling. In a large bowl, with mixer at medium speed, beat butter until smooth. Reduce speed to low; gradually be in confectioners sugar, marshallow fluff and International Delight.
Spread filling onto flat side of cookie and top with a second cookie.