1. Preheat your oven to 350 F (175 C). Lightly grease a 9×13 inch baking pan with butter or cooking spray, then line it with parchment paper, leaving an overhang on the sides to easily lift the bars out later.

2. In a large mixing bowl, using an electric mixer, cream together the softened butter, granulated sugar, and brown sugar until the mixture is light and fluffy. This usually takes about 2-3 minutes.

3. Beat in the large egg and vanilla extract until well combined. Then, add the pumpkin puree and mix until just incorporated. Be careful not to overmix at this stage.

4. In a separate medium bowl, whisk together the all-purpose flour, baking soda, salt, ground cinnamon, ground nutmeg, ground ginger, and ground cloves. Ensure all the dry ingredients are evenly distributed.

5. Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Stop mixing as soon as no dry streaks of flour remain.

6. Gently fold in the semi-sweet chocolate chips by hand using a spatula. Distribute them evenly throughout the batter.

7. Spread the batter evenly into your prepared 9×13 inch baking pan. Bake for 25-30 minutes, or until a wooden skewer or toothpick inserted into the center comes out with moist crumbs attached, but not wet batter. The edges should be lightly golden brown.

8. Allow the bars to cool completely in the pan on a wire rack before lifting them out using the parchment paper overhang. Once completely cool, cut them into squares or rectangles. Cooling fully is important for clean cuts and a firm texture.