Preheat your oven to 350°F (175°C). Butter an 8x8-inch (20x20 cm) baking pan and set aside.
In a large mixing bowl, combine the oat flour, pumpkin pie spice, salt, coconut sugar, chocolate chips, and walnut pieces (if using). Whisk well to remove any lumps.
Then, add the wet ingredients. Whisk in the melted coconut oil, eggs, pumpkin puree, and vanilla extract until well combined.
Transfer the blondie batter to the prepared baking pan and spread it evenly.
Bake in the preheated oven for approximately 30-35 minutes. A toothpick should come out with some moist crumbs attached.
Allow the blondies to cool in the pan for about 30 minutes, then cut and serve.
Notes
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.