Preheat oven to 350°F (175°C).
In a large bowl, cream together butter, brown sugar, and granulated sugar until smooth.
Beat in eggs one at a time, then stir in vanilla.
Combine flour, baking soda, cinnamon, and salt; stir into the creamed mixture until just blended.
Mix in oats and raisins.
Drop by rounded teaspoonfuls onto ungreased cookie sheets.
Bake for 10 to 12 minutes, or until golden brown.
Allow cookies to cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Once cookies are completely cool, place a scoop of vanilla ice cream between two cookies to make a sandwich.
Wrap each sandwich in plastic wrap and freeze for at least 1 hour before serving.