Preheat oven to 350 degrees. In a mixing bowl whisk together flour, oats, baking soda, salt, cinnamon, nutmeg and ginger for 30 seconds, set aside.
In the bowl of an electric stand mixer fitted with the paddle attachment, whip together butter, brown sugar and granulated sugar until creamy (occasionally stop and scrape down sides and bottom of bowl throughout entire mixing process). Blend in egg then blend in vanilla extract and pumpkin puree. With mixer set on low speed, slowly add in dry ingredients and mix until combined. Mix in chocolate chips and pecans (if you want some chocolate to show through set some aside to press into tops before baking). Let batter rest 5 - 10 minutes (this just gives the oats some time to absorb the liquids so batter isn't so sticky and cookies don't spread so much).
Scoop dough out 2 Tbsp at a time (I used a 1 1/2-inch cookie scoop, which I recommend using for evenly shaped cookies and fill it heaping), and drop onto Silpat or parchment paper lined baking sheets, spacing cookies 2-inches apart. Bake in preheated oven 12 - 14 minutes. Allow to cool on baking sheet several minutes then transfer to a wire rack to cool completely. Store in an airtight container.