Preheat oven to 350ºF. Line a 9×13-inch baking pan with parchment paper and grease with butter or nonstick cooking spray. In a medium bowl, whisk together the flour, baking soda, and salt until combined; set aside.

In the bowl of an electric stand mixer fitted with a paddle attachment, cream the butter until smooth. Add in both sugars and mix on high for 3 minutes until light and fluffy. Add the eggs, one at a time, mixing after each addition until combined. Add in the vanilla. Then stir in the pudding mix.

With mixer set on low speed, slowly add the flour mixture into the wet mixture until everything has been incorporated. Gently stir in chopped Oreos and pumpkin chips. Turn batter out into prepared pan, pressing evenly with greased/buttered hands.

Bake for 20-22 minutes, or until top and edges are set. A toothpick inserted in the center should come out clean, or with a few moist crumbs attached. Allow bars to cool in pan for at least 30 minutes before slicing and serving. Bars will keep airtight at room temperature for up to 1 week, or in the freezer for up to 6 months.