Heat oven to 350°F. Butter a 9x5-inch loaf pan and line the long sides with parchment.
Whisk flour, baking soda, baking powder, salt, cinnamon, ginger, nutmeg, and cloves in a large bowl.
In another bowl, whisk pumpkin, brown sugar, granulated sugar, beaten egg, oil, milk, and vanilla until smooth.
Pour the wet mixture into the dry ingredients. Stir gently until just combined with no dry streaks.
Fold in the pecans, keeping the batter thick and slightly lumpy.
Scrape batter into the pan and smooth the top. Sprinkle turbinado sugar over the surface, if using.
Bake 55–65 minutes, until a tester in the center comes out clean or with a few moist crumbs.
Cool 10 minutes in the pan, then lift out and cool completely on a rack before slicing.