Heat oil in a large pot, add onion and sauté. Cook until soft, about 5 minutes.
Add squash, cook until soft, 8-10 minutes.
Add garlic, sage, rosemary, ginger, stir until fragrant, 1 minute.
Add 3 cups broth, bring to boil, reduce to simmer. Cook until squash is tender, 20-30 minutes.
Let cool slightly, then blend until smooth (add water if needed). If too thick, add more broth and blend.
Garnish and serve with bread.