This is a zippy Southwestern-flavored black bean soup. We make it with canned beans so it comes together in minutes. If you have leftovers, pack them up in individual serving containers for lunch the next day.
- Heat oil in a large saucepan over medium heat. Add onion and cook, stirring, until beginning to soften, 2 to 3 minutes. Add chili powder and cumin and cook, stirring, 1 minute more. Add beans, water, salsa and salt. Bring to a boil; reduce heat and simmer for 10 minutes. Remove from the heat and stir in lime juice.
- Transfer half the soup to a blender and puree (use caution when pureeing hot liquids). Stir the puree back into the saucepan. Serve garnished with sour cream and cilantro, if desired.