Smoky Black Bean and Sweet Potato Soup

I concocted this based on what I had in the refrigerator. My houseguest liked it so much he asked for the recipe. Here it is, as best I remember.

1 1/2 cups dried black beans
6 cups vegetable stock (I use this)
1 Tbsp canola oil
1 small yellow onion, diced
2 shallots, diced
2 cloves garlic, minced
3 stalks celery, diced
2 carrots, diced
2 small sweet potatoes, peeled and diced
3/4 tsp ground cumin
3/4 tsp ground coriander
1 tsp smoked paprika
1/2 tsp chipotle chile powder
1 tsp RealSalt
2 bay leaves
2 Tbsp tomato paste
1/2 cup pumpkin puree
1/3 cup lime juice
Sour cream
Crunchy tortilla strips
Chopped cilantro

Pick over the black beans, removing any stones. Wash them, then soak overnight, or quick-soak them by bringing them to a boil, removing from the heat, and letting stand for one hour. Cook the beans in vegetable stock until barely tender (10 minutes on HIGH in a pressure cooker). Set aside; do not drain.

In a medium skillet, cook onions, shallots and garlic in canola oil over medium heat until softened. Add celery, carrots and sweet potato. Cook a moment, stirring, then add cumin, coriander, paprika and chipotle. Cook until spices are fragrant, then transfer with beans and liquid to bowl of a slow cooker. Add salt, bay leaves, tomato paste and pumpkin puree. Cook on HIGH for 2 hours or until vegetables are tender. (This can also be done on the stovetop but I like the relaxed time aspect of a slow cooker.)

Stir in lime juice. Ladle into bowls, removing bay leaves as you come across them. Top with dollops of sour cream and sprinklings of tortilla strips and cilantro.