Vegan Black and White Bean Soup

1 tablespoon olive oil

1 onion, chopped

1 celery rib, chopped

1 tablespoon crushed garlic

1 teaspoon thyme

1 (14.5 ounce) can black beans, drained

8 cups vegetable broth, divided

1 teaspoon ground cumin

1 (14.5 ounce) can white beans, drained

½ teaspoon dried sage

Heat the oil in a large stock pot over medium heat. Cook the onion, celery, garlic, and thyme together in the hot oil until the celery is soft, 7 to 10 minutes. Add the black beans, 4 cups vegetable broth, and the cumin to the pot; mix to combine. Stir the white beans, the remaining vegetable broth, and the sage into the mixture; bring to a gentle boil and simmer 30 minutes.