01 - Preheat oven to 350°F. Line baking sheets with parchment paper.
02 - In a large bowl, cream together butter, brown sugar, and granulated sugar until light and fluffy.
03 - Beat in eggs one at a time, then add vanilla extract.
04 - In a separate bowl, whisk flour, baking soda, salt, and cinnamon.
05 - Gradually add dry ingredients to wet ingredients, mixing just until combined. Stir in oats and raisins.
06 - Drop tablespoonfuls of dough onto prepared baking sheets, spacing 2 inches apart.
07 - Bake for 12-14 minutes, or until edges are golden and centers are just set. Cool on baking sheets for 5 minutes, then transfer to a wire rack.
08 - For the frosting, in a saucepan, melt butter over medium heat. Stir in brown sugar and milk; bring to a gentle boil. Boil for 2 minutes, stirring constantly. Remove from heat and let cool for 2 minutes.
09 - Gradually whisk in powdered sugar and a pinch of salt until smooth and spreadable.
10 - Spread caramel frosting over cooled cookies. Let set before serving.