Preheat oven to 350°F. Grease a 9x5-inch loaf pan and line with parchment paper.
In a medium bowl, whisk together flour, cinnamon, nutmeg, ginger, cloves, baking soda, and salt. Set aside.
In a large bowl, combine the granulated and brown sugars, pumpkin purée, sourdough discard, vegetable oil, and egg. Whisk until smooth.
Add the dry ingredients to the wet ingredients and stir until combined. Fold in the chocolate chunks, reserving at least 2 Tablespoons of chocolate chunks for the topping. Pour the batter into the prepared pan and spread evenly. Sprinkle the top with turbinado sugar and the remaining chocolate chunks.
Bake for 60 minutes, then tent loosely with aluminum foil and bake for an additional 10-15 minutes until a toothpick inserted in the center comes out clean.
Remove from the oven and let cool for 10 minutes in the pan. Then remove the loaf from the pan (you can lift it up with the parchment paper) and transfer to a cooling rack to cool completely. Slice and serve.
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Notes
While it's not needed for leavening purposes, if you'd like to make this recipe with active sourdough starter instead of discard, you can. To do so, make a 1:1 substitution. If you loved this recipe, you might also love my Sourdough Discard Pumpkin Bread!