Rinse the 16-bean mix under cold water and drain.
(Optional) Soak beans overnight for faster cooking, or use the quick-soak method (boil for 2 minutes, then let sit for 1 hour).
Heat olive oil in a large pot over medium heat.
Add onion, garlic, carrots, and celery. Sauté for 5 minutes until softened.
Add the soaked (or unsoaked) beans, diced tomatoes, broth, smoked paprika, cumin, bay leaf, black pepper, and salt.
Bring to a boil, then reduce heat to low and simmer for 1 to 1.5 hours (or until beans are tender). Stir occasionally.
Once beans are soft, taste and adjust salt and pepper as needed.
Stir in lemon juice (optional) for brightness.
Remove the bay leaf.
Garnish with fresh parsley and serve warm with crusty bread.
