Preheat your oven to 350 degrees Fahrenheit and line a baking sheet with parchment paper.
Sift together the flour, baking soda, and pumpkin pie spice into the same bowl, then stir in the oats.
In a small bowl, mix together the butter, sugar, molasses, and pumpkin with a mixer until well combined. Add the egg and vanilla and mix again.
Pour in the flour/oat mixture and beat until smooth. Cover with plastic wrap and set in the fridge for at least 30 minutes to chill.
After chilling, place dough onto a baking sheet using a tablespoon. Bake for 8-12 minutes or until lightly browned.
Place cookie sheet on a rack to cool and then transfer cookies to the rack. Allow to cool completely.
To make the glaze, sift the powdered sugar into a bowl and stir in the milk and maple syrup until smooth. Use a fork to drizzle over the cookies. Let sit for a couple of minutes to allow the glaze to set and then enjoy!