In a large stockpot, heat the oil until shimmering. Add the onion, carrots, and celery and season to taste with salt and pepper. Cook until the onions start to go clear.
Add the beans, water, tomato sauce, and spice mix. Simmer for 15 to 20 minutes or until the carrots are tender.
With an immersion blender, blend the soup to your preferred texture. Adjust the seasonings and serve with chopped fresh cilantro, if desired.
To freeze: Cool the soup and divide it into meal-sized containers with lids. Label with the date and contents. Chill the containers in the refrigerator until completely cold. This helps the beans freeze more quickly, reducing the risk of freezer burn. Place the containers in the freezer for up to 6 weeks. Reheat before serving.Navy beans or Cannellini beans can be used instead of Great Northern Beans.Instead of using canned beans, you can use 8 cups cooked great northern beans or other white beans. Head here for instructions on how to cook dried beans.