The night before making the soup, place your beans in water to soak overnight. The next day, drain and rinse the beans, discarding any loose skins. Place the rinsed beans in a large pot and cover with about 6 cups of water. Bring this to a full boil and skim off any foam before adding a small piece of kombu seaweed to the pot for some extra nutrition, flavor, and digestive help (ahem!). Next, cover the pot and bring the beans to a simmer. You’ll let them cook for about an hour, checking every 30 minutes to find the perfect cooking time for your preference.
Once the beans are done cooking to your liking, drain the water and set beans aside. Then place the onion and 1/2 cup of the broth in a large skillet or saucepan—cook them over medium heat with the lid on. When the onions have softened, remove the lid and cook off an excess liquid. This process can be repeated until the onions have sufficiently caramelized—the longer they cook, the better they will taste. Just keep an eye on them so they don’t burn beyond repair. Add the cumin and garlic toward the end of cooking the onion, and let these ingredients mingle for about 5 minutes.
Combine the cooked beans, tomatoes, sea salt, pumpkin puree, remaining vegetable broth, and softened onion in a large pot or bowl. Then, blend this mixture in small batches until just incorporated (or use an immersion blender)—you want a slightly chunky texture. Be sure to not fill the blender too much as hot liquid expands. Return the blended soup to a large pot and let it simmer for about 15 minutes, then stir in the red wine vinegar. If the soup is too thick for your liking, more water or broth can be added to thin it out. Give it a taste and add more salt or vinegar if you please. We top our soup with a variety of things, but our favorites would be avocado, spiced-pumpkin seeds, or sweet-potato-almond crackers.