Preheat your oven to 350°F (175°C) and line an 8x8-inch baking dish with parchment paper.

In a large mixing bowl, combine pumpkin puree, maple syrup, nut butter, egg (or flax egg), and vanilla extract. Whisk until smooth.

Add rolled oats, baking powder, pumpkin pie spice, and salt to the wet mixture. Stir until fully incorporated.

Fold in any optional mix-ins like chocolate chips or dried fruit.

Pour the mixture into the prepared baking dish, spreading it evenly.

Bake for 28-32 minutes until the edges are golden brown and a toothpick comes out mostly clean.

Allow to cool completely in the pan before slicing into 12 squares.