Preheat oven to 300°F. Bake bread cubes until dried out, about 10-15 minutes. (Alternatively, you can let them sit out at room temperature for 8-12 hours.)
Heat a skillet to medium-high heat and add olive oil. Add onion, celery, sweet potatoes and carrots and cook until tender. It is okay for sweet potatoes to not be completely soft.
In a large bowl, combine bread cubes, seasoning and vegetable mixture. Toss in broth and egg.
Transfer stuffing to a slow cooker coated with nonstick spray. Cover and cook on LOW for 4 hours.
