Prep:Heat oven to 350°F. Lightly grease a 9×5-inch loaf pan and line with parchment (leave overhang - it makes lifting the loaf out so easy). Get your ingredients ready.
Mix dry ingredients:In a medium bowl, whisk together the flour, baking soda, baking powder, salt, and spices.Tip: Whisk well so the baking soda doesn’t clump and cause uneven pockets.
Mix wet ingredients:In a large bowl, whisk the sugar, pumpkin purée, oil, eggs, and vanilla until smooth and glossy.If you're using half white/half brown sugar, make sure the brown sugar is fully dissolved.
1 cup sugar, 1 cup pumpkin purée, ½ cup oil, 2 large eggs, 1 teaspoon vanilla extract
Combine batter:Add the dry ingredients into the wet and stir gently until just combined. Stop when you no longer see big streaks of flour — overmixing = dense bread.
Make the twilight batter:Scoop about half of the batter into a smaller bowl. Add the molasses, dark brown sugar, extra spice, and cocoa powder. Fold gently until dark and smooth.(The cocoa is just for color, not flavor. I don't particularly enjoy the combination of pumpkin and chocolate, so I can assure you - it won't taste chocolatey.)
about ½ of the above pumpkin batter, 2 tablespoons sweet molasses, 2 tablespoons dark brown sugar, ½ teaspoon extra spice, 1 tablespoon unsweetened cocoa powder
Layer the batter:Spread half of the dark batter in the bottom of the pan. Dollop half of the pumpkin batter over it in spoonfuls. Repeat both batters.
Create the swirls:Use a butter knife to swirl a few figure-8s, or use a fork to spiral through the batter. Don't overdo it! You want pretty ribbons, not a fully blended batter.
Bake:Sprinkle with turbinado sugar for sparkle and crunch (optional but magical). Bake the loaf for 50–60 minutes.At 40 minutes, check the top - if it’s browning quickly, tent loosely with foil. It’s done when a toothpick comes out mostly clean or with moist crumbs (no wet batter).Let the loaf cool in the pan for 15 minutes (this sets the structure). Lift out using the parchment and transfer to a cooling rack. Wait until mostly cool to slice - this is when the swirls look their best!
2 tablespoons turbinado sugar
Notes
Don’t skip the parchment. The overhang of parchment guarantees clean release, even when the bread is still warm.
Use canned pumpkin purée, not pumpkin pie filling.
Don’t over-swirl. Two or three passes with a butter knife, or spiralling through once with a fork (my preferred technique) is plenty.
Cocoa powder = color, not flavor. Leave it out if you prefer a lighter swirl.