Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a mixing bowl, whisk together the flour, baking powder, baking soda, pumpkin pie spice, and salt.

In another bowl, mix the pumpkin puree, sugar, egg, vanilla extract, and espresso powder until smooth.

Gradually add the dry ingredients to the wet ingredients, mixing until combined.

Fold in the chopped walnuts and chocolate chips.

Divide the dough in half and shape each half into a log about 12 inches long on the prepared baking sheet.

Bake for 25-30 minutes or until golden brown and firm to the touch.

Remove from the oven and let cool for 10 minutes.

Using a serrated knife, slice the logs diagonally into 1-inch thick pieces.

Place the slices back on the baking sheet cut side down and bake for an additional 10-15 minutes until crisp.

Let cool completely before serving.