Heat the oven to 350°F (175°C). Grease a 9 x 5-inch loaf pan and line it with parchment paper, leaving enough overhang to lift the finished loaf out easily.

Whisk the flour, baking soda, baking powder, salt, cinnamon, nutmeg, cloves, and ginger or allspice together in a medium bowl.

In a separate large bowl, whisk the melted, slightly cooled butter with both sugars. Add the eggs one at a time, then whisk in the pumpkin puree and vanilla.

Add the dry ingredients to the pumpkin mixture and fold just until no dry flour remains. Avoid overmixing.

Fold about three-quarters of the chocolate chunks into the batter. Transfer the batter to the prepared pan and scatter the remaining chunks over the surface.

Bake for 55–70 minutes, until a toothpick inserted in the center comes out with a few moist crumbs but no wet batter. If the top browns too quickly, loosely cover it with foil during the final 15–20 minutes.

Cool the loaf in the pan for 15–20 minutes, then lift it onto a rack and cool completely before slicing. The crumb continues to set as the bread cools.