Any curry powder will work here, but we prefer a turmeric-forward blend for its warm flavor and golden color. Madras curry powder will make the soup a bit spicier, while vadouvan is more mellow and savory with subtle onion and garlic notes. You can also make homemade curry powder, like this aromatic, chile-free Trinidadian version from Epicurious.
If you’d rather skip it, you can season the soup with cumin, coriander, or smoked paprika instead—or leave the spice out entirely for a more classic squash soup.