Step 1

Soak the beans overnight: Sort the bean mix, removing broken beans, stones, or dirt clods. Rinse the beans and put them in a large container with the salt. Cover with 2 quarts water. Let the beans soak for at least 8 hours, or overnight.

Step 2

Heat the oil in the pressure cooker pot over medium-high heat until shimmering, about 3 minutes. Add the onion, carrot, celery, garlic, and 1/2 teaspoon salt. Saute until the onions are softened and browning around the edges, about 8 minutes. Stir in the chili powder and the coriander, and saute for one minute to toast the spices.

Step 3

Drain and rinse the beans. Pour the beans into the pressure cooker. Stir in the water, tomatoes, and bay leaves. Lock the lid on the pressure cooker, and cook at high pressure for 18 minutes in an electric PC, or 15 minutes in a stovetop PC. Turn off the heat and let the pressure release naturally, about 20 minutes. Remove the lid carefully, opening away from you - even when it’s not under pressure, the steam in the cooker is very hot.

Step 4

Fish out the bay leaves and discard. Puree 2 cups of beans and liquid - I use a 4 cup measure and my stick blender - and stir back into the pot. Taste the soup and add salt until the soup tastes sweet and full bodied, and you can just feel the taste of salt on the tip of your tongue. (I added 2 teaspoons of kosher salt to get the taste I wanted.) Serve.