Preheat oven to 350 degrees.
In large mixing bowl, whisk together brown sugar, flour, baking soda, baking powder, salt, and cinnamon. Cut butter into flour mixture with pastry blender, one tablespoon at a time.
In a separate bowl, combine pumpkin, egg, sour cream, and vanilla. Add pumpkin mixture to flour mixture and stir until combined.
Fold in walnuts and raisins.
Scoop by three tablespoonful scoop size about an inch apart on ungreased baking sheet. Bake 15 to 20 minutes or until toothpick placed in center of cookie comes out clean.