Salsa Chicken and Black Bean Soup

I used a 6.5 quart crockpot. You will need a 4 quart or larger. If you know you are going to make this the night before (yay for meal planning!) soak the black beans in enough water to cover and another 2 inches overnight. In the morning, drain the water and rinse the beans. If you don't have super hard water or live in a super high altitude, you can quick soak the beans by pouring boiling water over them and let them sit for an hour or two. I did an hour, but 2 would really be better if you have the time. Drain and rinse the beans. Add to the crockpot. Put in the chicken, and add the broth and salsa. Pour in the corn and mushrooms, and add the cumin. Stir, but don't disturb the beans---let them stay at the bottom of the pot, closest to the heating element. Cover and cook on high for 9 hours. Yup. High. For 9 hours. It took a crazy long time for the beans to soften, but they did. If you are using beans you soaked overnight, canned beans, or pre-cooked beans, you can cook on low for 6-8 hours, or on high for 4-5--similar to normal soup-cooking time. If you'd like to thicken the broth (I did this), you can use your immersible blender (I love that thing) to blend a bit of the beans and chicken. If you don't have one, scoop out 2 cups of the soup and carefully blend in your traditonal blender. Stir the mixture back into the crockpot. Stir in the 1/2 cup of sour cream before serving, and garnish with shredded cheese and avocado slices.