Preheat oven to 350°F.
Line a baking sheet with parchment paper or a silpat liner.
Combine the dry ingredients in a bowl; flour, baking powder, baking soda, salt, pumpkin pie spice. Stir and set aside.
Spread the pumpkin puree out onto a plate and use paper towels to blot away the excess moisture. Keep blotting with a fresh paper towel until the paper towel no longer becomes immediately saturated. It will take several paper towels.
Place white sugar, brown sugar, blotted pumpkin purée and melted butter in the bowl of a stand mixer. Mix everything together until combined.
Add the egg yolk and vanilla and mix those in until completely combined.
Add the reserved dry ingredients (except the oats) to the batter.
Mix everything together until totally incorporated.
Add oat meal, stir on low speed to combine.
Add chocolate chips and stir till incorporated.
Use a cookie scoop to scoop out ping pong ball sized mounds of dough.
Use your fingers to gently press down each dough ball slightly into a round disc.
Sprinkle a few flakes of Maldon salt onto each cookie.
Bake for 14 minutes or until cookies start to brown slightly.
Allow cookies to rest on cookie sheet for 5 minutes.
Transfer cookies to a wire rack to cool completely.