To the dutch oven, add the onion, carrots and celery to the pot with the bacon fat. Saute until softened, about 5 minutes. Add the garlic and saute until fragrant. Stir in the sweet potatoes, cumin, and paprika. Pour in the chicken broth into the pot, cover and bring the soup to a boil, then reduce the heat and simmer until the potatoes are fork-tender, about 30 minutes. Stir in cream, heat just until steaming.