Grind oats in a blender or food processor. They should have a mealy texture with a few whole oats. Transfer to a medium bowl and stir in flour, baking soda, salt and spices. 

Beat butter in a large bowl with an electric mixer until fluffy. Add granulated sugar, brown sugar, egg and vanilla; beat until smooth and creamy. With the mixer running, add the dry ingredients, beating on low speed until just combined. Stir in raisins. Chill the dough in the refrigerator for a few hours.

When you are ready to bake, preheat the oven to 350 degrees F. Line 2 baking sheets with lightly greased parchment paper.

Drop the dough by heaping spoonfuls, at least 1 inch apart, onto the prepared baking sheets. Bake cookies until lightly golden around the edges, about 12-13 minutes. Cool the cookies for 2 minutes on the baking sheets, then transfer to wire racks to cool completely.