Note: This frosting is a cross between a typical frosting and a glaze. By adding milk, it becomes a bit more spreadable than the traditional cream cheese frosting. If you want it thicker, add the milk, 1 tablespoon at a time, until you reach your desired consistency.
In a mixer fitted with the paddle attachment, combine remaining oil, sugar, and vanilla. Add eggs and mix until well combined.
In a medium bowl, combine flour, baking soda, cinnamon, and salt. Slowly add dry ingredients to wet mixture and combine. Add carrots and raisins and mix until just combined. Transfer mixture to cast iron skillet and bake for 35-45 minutes until a toothpick inserted into the center comes out clean. Set aside to cool.
Meanwhile, make the frosting. Combine cream cheese, milk and vanilla, and mix until well combined. Slowly add confectioners’ sugar and mix until completely smooth. When the cake is cooled, top it with frosting and serve.