Add pumpkin, egg, and vanilla and mix until well combined.
In separate bowl, mix flour, oats, baking soda, cinnamon, and salt.
Turn mixer on low speed and gradually add in flour mixture, scraping down sides of mixing bowl halfway through.
Remove bowl from mixer and stir in raisins.
Drop by rounded tablespoons onto cookie sheets lined with foil and sprayed lightly with cooking spray.
Bake in preheated oven at 350 degrees for 12-14 minutes until lightly browned.
Transfer cookies to cooling rack.
For glaze, whisk together confectioner's sugar and milk 1 tablespoon at a time until sugar is completely melted and you have a thin icing consistency (you need less milk than you think).
Drizzle icing over cookies on cooling rack and allow icing to harden for a few minutes before placing in cookie jar or air tight container.