Preheat an oven to 350°F.

Prepare a baking sheet by spraying with baking spray or covering with parchment paper or a silicone mat.

Combine the butter and sugar in a bowl and mix until light and fluffy.

Add the eggs, one a time, mixing to combine well after adding each one.

Add the pumpkin.

Combine the flour, baking powder, pumpkin pie spice, and cinnamon in a small bowl and add to the batter.

Mix just until incorporated.

Place the cookie dough into a rough log shape on the prepared baking sheet and form into 2 logs about 9-inches long by 2-inches wide.

Place the dough log into the preheated oven and bake for 25 to 30 minutes or until the top looks completely dried.

Remove from the oven and allow to cool for 5-minutes.

Reduce the oven temperature to 325°F.

Using a bread knife, or another serrated knife, cut the cookie log into 1-inch-thick slices.

Place each slice back on the cookie sheet, cut side down.

Bake the biscotti slices for an additional 40 to 45 minutes or until the biscotti are dried.

Remove from the oven and allow to cool completely before storing in an airtight container for up to 2 weeks.