Heat oven to 350 degrees. Lightly grease a 9 x 13 inch pan.
Beat the butter until creamy. Beat together the flour, brown sugar, sugar, egg, apple butter, baking soda, apple pie spice and raisins until well blended. Spread into the prepared baking pan.
Bake for 25 minutes, then remove from oven and cool completely.
For the frosting mix together the melted butter, powdered sugar, vanilla and milk. Drizzle over the top of the cooled cake.