Roasted Sweet Potato and Tomato Soup with Herbs
The sweet potatoes give this soup a rich creaminess, even though it contains no cream or milk. Chilled, it can be served as a starter on a warm Indian summer night.
Serves 8 to 10 (makes about 3 quarts)
3 pounds sweet potatoes (5 to 6 medium)
¼ cup olive oil, plus more for rubbing on the sweet potatoes (about 2 tablespoons)
6 plum tomatoes (about 1½ pounds), cored and halved
4 garlic cloves
1 tablespoon balsamic vinegar
4 tablespoons unsalted butter
1 red onion, chopped
2 carrots, chopped
2 celery stalks, chopped
6 cups chicken or vegetable broth
2 teaspoons sea salt, plus more to taste
1 teaspoon freshly ground black pepper, plus more to taste
Leaves from 8 to 10 fresh thyme sprigs (about 3 tablespoons) or 2 teaspoons dried, crumbled, plus more for garnish
2 tablespoons chopped fresh chives
1 tablespoon chopped fresh sage leaves or 1 teaspoon dried, crumbled, plus more for garnish
Juice of 2 oranges
1. Preheat the oven to 450°F.
2. Rub the sweet potatoes with a small amount of olive oil, place them on a baking sheet with sides, and roast for 40 to 45 minutes, until they are soft to the squeeze and tender when pierced with a knife. When they are cool enough to handle, remove and discard their skins.
3. While the sweet potatoes roast, toss the tomatoes and garlic with 2 tablespoons of the olive oil and the balsamic vinegar on a baking sheet with sides. Roast (along with the sweet potatoes) until the tomatoes are squishy and the skins slightly shriveled, 30 to 35 minutes. When they are cool enough to handle, tear the tomatoes into small pieces over a small bowl.
4. Melt the butter and the remaining 2 tablespoons of olive oil in a large saucepan over medium heat. Add the onion and cook, stirring often, until it is soft and translucent, about 10 minutes. Add the carrots and celery and cook, stirring often, until the vegetables are soft, about 10 minutes longer. Add the broth, 2 teaspoons salt, and 1 teaspoon pepper, reduce the heat to low, and simmer, uncovered, for about 20 minutes. Add the sweet potato flesh and dried herbs, if using, to the soup and simmer about 20 minutes longer, stirring occasionally. Remove from the heat, stir in the fresh thyme, chives, and sage, and allow the soup to cool slightly.
5. Working in batches if necessary, pour the soup into the bowl of a food processor or the jar of a blender fitted with a metal blade (or puree it directly in the pot with an immersion blender) until it is smooth. Return the pureed soup to the pot, add the tomatoes and their liquid and the orange juice, and stir to combine, Season with additional salt and pepper to taste. Serve warm or chilled, topped with fresh sage and thyme.