Heat oil in a large pot or Dutch oven over medium heat. Add the onion and ginger. Cook 5 minutes or until softened, stirring occasionally.
Stir in the squash, potato, maple syrup, stock and orange zest and juice. Season generously with salt (start with 1 ½ teaspoons). Bring to a simmer, then adjust heat to medium-low. Cover the pot and cook until the squash is soft when pierced with a fork, about 25 minutes.
Puree the soup in batches in a blender or with an immersion hand blender until very smooth.
Garnish with the herbs and pumpkin seeds, and a spoonful of your choice of yogurt or cream.
The soup keeps up to 5 days in the refrigerator. You can also freeze in small containers up to a month.
How to peel and cut a butternut squash:
On a cutting board, slice ¼-inch off the stem and bottom with a sharp knife.
Cut the squash in half at the point where the straight part of the neck meets the rounded section.
Slice both sections in half. Scoop out the seeds.
Use a vegetable peeler to scrape off the skin. Cut the squash into chunks.