Preheat oven to 350 degrees F. Coat 3 baking sheets with cooking spray.
Whisk pastry flour, all-purpose flour, baking powder, baking soda, salt, cinnamon, ginger, allspice, and nutmeg in a large bowl.
Whisk pumpkin, brown sugar (or Splenda), eggs, oil, and molasses in a second bowl until well combined. Stir the wet ingredients and raisins into the dry ingredients until no traces of dry ingredients remain.
Drop the batter by level tablespoonfuls onto the prepared baking sheets, spacing the cookies 1 1/2 inches apart.
Bake the cookies until firm to the touch and lightly golden on top, 10 to 12 minutes, switching the pans back to front and top to bottom halfway through. Transfer to a wire rack and let cool.