Heat a large pot to medium-high heat. Add the oil/ghee. Then add the onion, garlic, celery, and carrots. Sauté them, stirring often until vegetables are fork-tender.
Add the cumin, curry, and salt to the pot to let it toast and get fragrant for a minute.
Add the broth, water, beans, and tomatoes. Let them come to a gentle simmer for a few minutes.
Add a few handfuls of spinach and stir around. Turn off the heat as soon as the spinach is wilted. (The spinach will wilt very quickly).
Serve immediately and refrigerate leftovers for up to a week.