Preheat an oven to 350 degrees. Line two baking sheets with parchment paper.
In a large bowl combine flour, pumpkin pie spice, baking soda, and kosher salt.
In another large mixing bowl using a hand mixer, beat the butter and brown sugar together until light and fluffy. Next, add in an egg, pumpkin puree, and maple syrup. Beat until combined. Gradually add in the flour mixture making sure the batter is well combined.
Fold in the oats and pecans if using. Cover the dough in plastic wrap and refrigerate for at least 30 minutes.
Scoop out roughly 16 cookie dough sized balls. I used an ice cream scooper! Place the cookie dough balls on the baking sheet spaced about 2 inches apart. Slightly flatten the ball with your hand or spatula and bake for about 14 to 15 minutes until lightly browned. Remove from the oven and cool completely.
In a small bowl, whisk powdered sugar, maple syrup, and pumpkin pie spice together. Add in 1 tbsp milk at a time until desired consistency. Drizzle the glazed over the cooled cookies. Let the glaze stand for a few minutes until set.