1. Preheat oven to 375 degrees Fahrenheit.
2. In a large bowl, combine oil, shallots, and seasoning. Using an immersion blender, blend mixture until it forms a loose paste.
3. Line sweet potatoes standing up in an oven-to-table dish. Pour shallot oil marinade on top.
4. Cover and bake for one and a half hours. Uncover and bake for an additional 45 minutes or until slightly crisp on top.