Step 1) Combine flour, brown sugar, ginger, cinnamon, nutmeg, baking soda, cloves and salt in a medium bowl; set aside.
Step 2) Combine molasses, buttermilk, oil and egg until well blended in a large bowl. Add flour mixture, then raisins, stirring to combine. Cover and refrigerate 1 hour.
Step 3) Preheat oven to 375°F. Spray 2 large baking sheets with cooking spray.
Step 4) Drop dough by rounded tablespoonfuls 2 inches apart onto prepared baking sheets. Bake 7 to 9 minutes, or until set and no imprint remains when lightly touched. Cool on wire rack.
To prepare Glaze: Combine powdered sugar, milk and vanilla; stir well. Spoon into resealable plastic bag. Cut small hole in corner; drizzle glaze over cookies.
Tip: Before measuring molasses, spray measuring cup with cooking spray.