In a large bowl, cream together the sugar and shortening until smooth. Stir in the molasses and vanilla. Combine the flour, cinnamon, baking soda and salt; stir into the mixture alternately with the sour milk. Cover the dough and chill for at least one hour.
Preheat the oven to 375 degrees F (190 degrees C).Grease cookie sheets. On a lightly floured surface, roll out about 1/3 of the dough to 1/4 inch in thickness. Cut into circles about 3 inches in diameter using a cookie cutter or drinking glass. Place cookies 2 inches apart onto the prepared cookies sheets. Place a raisin onto the center of each cookie.
Bake for 8 to 10 minutes in the preheated oven, or until lightly browned. Allow cookies to cool on baking sheet for 5 minutes before removing to a wire rack to cool completely.