Rinse the black beans and soak them in the water overnight.
Rinse and discard the bean water.
Add the beans and bay leaf to a heavy duty stock/soup pot and bring the beans to a boil with the broth/water on high heat.
As the liquid begins to boil, reduce the flame to medium. The beans should be cooked until tender, this should take 1hr - 2 hours.
Replenish with water if the liquid levels drop drastically, a cup at the maximum should be enough. You should have hardly any liquid left.
Prepare the sofrito by adding the oil to a small frying pan on medium heat.
Sauté the minced garlic and onions for one minute then add the peppers and stir in the cumin, oregano and black pepper.
Continue to cook for another 2-3 minutes.
Pour the minced mixture into the soup pot and stir.
Use an immersion blender and pulse the black bean soup no more than three times, it will break down further with time. If you don't have an immersion blender, ladle a cups worth of beans and puree in a food processor/conventional blender.
Finally, add the vinegar, sugar, pink salt and season to taste (add more if needed) and stir in the roasted red pepper if included.
Remove the bay leaf and serve with a dollop of dairy free sour cream.