If you use Vegetable stock this is a great and tasty Vegan / Vegetarian soup. Or you could use chicken stock...

This recipe makes 8 servings

Ingredients:

2 large sweet potatoes, (about ¾ lb / 450g each)
2 Tbsp (30 mL) extra-virgin olive oil
½ tsp (2 mL) salt
1 small onion, chopped
1 rib celery, chopped
1 carrot, chopped
2 cloves garlic, minced
1 tsp (5 mL) chopped fresh rosemary
¼ tsp (1 mL) ground black pepper
4 cups (1 L) vegetable stock (or chicken stock)
2 cups (500 mL) water

Method:

Pre-heat oven to 450°F (230°C)
Peel and roughly chop sweet potatoes; toss with half of the salt and oil. Roast on baking sheet stirring occasionally, until tender, about 20 minutes.
Meanwhile, heat Dutch oven with remaining oil over medium-high heat; sauté onion, celery, carrot, garlic, rosemary, pepper and remaining salt until softened.
Add roasted sweet potatoes, stock, and water; bring to boil. Reduce heat, cover and simmer, stirring occasionally, for 20 minutes.
Purée until smooth.