Preheat oven to 350 degrees F (180 degrees C).
Mix together All-Purpose Flour (1 cup), Quick Cooking Oats (1 cup), Brown Sugar (1/2 cup), and Baking Soda (1/4 teaspoon). Cut Butter (1/2 cup) into squares and add into dry ingredients. Work together with your hands until the mixture is coarse and crumbly.
Set 1/2 cup of the crumb mixture aside and mix it with the Pecans (1/2 cup).
Pour the rest of the mixture into a 9" x 9" pan lined with parchment paper, and press down evenly.
In a small bowl, whisk Canned Pumpkin Purée (1/2 cup), Egg (1), Maple Extract (1 teaspoon), Ground Cinnamon (1 pinch), Ground Nutmeg (1 pinch), Ground Allspice (1 pinch), and Salt (1 pinch) together and pour on top of the crumb mixture and spread evenly.
Sprinkle the reserved crumbles and pecans evenly on the top.
Bake in the preheated oven for 30-35 minutes.
Let cool for 10 minutes before removing from the pan.
Mix the Powdered Confectioners Sugar (1 cup), Maple Extract (1 teaspoon), and Whole Milk (3/2 teaspoon) together and drizzle on the slightly cooled bars. Serve and Enjoy.