Heat the oven: Heat the oven to 350°F. Grease a 9x5-inch loaf pan and line it with parchment, leaving overhang on the long sides.
Whisk the dry ingredients: Whisk the flour, baking soda, salt, and pumpkin pie spice together in a large bowl.
Whisk the wet ingredients: Whisk the pumpkin puree, both sugars, eggs, oil, and vanilla in a second bowl until smooth.
Combine gently: Pour the wet ingredients into the dry and stir just until no dry flour shows. A few lumps are fine — overmixing makes a tough loaf.
Fold in the cranberries: Toss the cranberries with 1 tablespoon of flour, then fold them in with the pecans. The flour dusting keeps the berries from sinking to the bottom.
Bake: Scrape the batter into the prepared pan and smooth the top. Bake 65 to 75 minutes, until a toothpick inserted in the center comes out clean or with a few moist crumbs.
Cool before slicing: Cool in the pan for 15 minutes, then lift the loaf out by the parchment and cool completely on a wire rack before slicing.