In the bowl of an electric mixer, mix butter and both sugars together until creamy on medium speed, then add the egg and mix again. Set aside.
In another bowl, mix flour, pumpkin pie spice, salt, baking soda and oats together.
Gradually add the flour mixture to the wet ingredients on low speed. Stir in the raisins until well incorporated.
Place cookie dough balls (I use a 2 tablespoon sized scoop) on a baking sheet and bake for 9-10 minutes. Allow the cookies to cool on the baking sheet for a few minutes, and then transfer them to a cooling rack.