3 tablespoons extra-virgin olive oil
3 garlic cloves, minced
1 small leek, (or 5 green onions) white and pale-green parts only, thinly sliced and rinsed well
1 tart green apple, such as Granny Smith, cored, peeled, and cut into 1-inch chunks
1 celery stalk, thinly sliced
1 teaspoon finely grated fresh ginger
2 pounds sweet potatoes, peeled and cut into 1-inch cubes
6 cups chicken stock
1 medium canned chipotle chile in adobo sauce (or substitute a half can of green chilies and some steak seasoning for the smoked effect.)
Coarse salt and freshly ground pepper

DIRECTIONS

Heat oil in a large pot over medium heat. Cook garlic and leek until soft and translucent, about 4 minutes. Add apple, celery, and ginger, and cook for 3 minutes. Add sweet potatoes and stock, and simmer until sweet potatoes are tender, about 15 minutes. Add chipotle chile.

Working in batches, transfer mixture to a blender, and puree until smooth, transferring soup to a large bowl as you work. (For safety, remove cap from hole in lid, and cover with a dish towel to prevent spattering.) Season with salt and pepper. Serve with sour cream and and chopped green onion bits.