Sort the beans and discard any stones or damaged beans.
Wash the beans in a colander.
(OPTIONAL) Then soak them in 3 times their volume of cold water for at least 4 hours or overnight (12 hours or more) so they will become more tender and cook faster. Rinse and drain. Reserve.
Cook beans: In a large, heavy-bottom pan over medium-high heat, bring the beans, with 6 cups of water and 1 tablespoon of oil, to a boil. Oil reduces foaming during the cooking process!
Then, cover the pan and reduce heat to medium-low. Let simmer for 60 minutes or until almost tender.
In a separate nonstick pan, heat 1 tbsp of oil over medium heat and cook the diced onion until translucent, stirring every now and then. Next, add the garlic and cook for about 60 seconds, stirring every now and then.
Mix the cooked onion and garlic into the almost cooked beans (about 30 minutes before cooking time comes to an end). Add the bay leaves, and stir in all the seasonings, spices, and the vinegar. The vinegar improves taste and reduces gassy elements. If salt is added at the beginning, it’ll toughen the beans.
Add 1 to 2 cups of water more, if needed. Cover and let simmer over medium-low heat for those 30 final minutes or until tender.
Stir and remove the bay leaves. If desired, remove about 1 cup of cooked black beans (grains and broth) and blend in a blender until smooth.
Add the blended beans back to the cooked beans and stir. This will make the beans thicker and tastier. Right before serving, sprinkle the chopped cilantro or parsley, if desired. Serve over white rice (a staple in Brazil) and with your fave meat, or used as a base for black bean soup and dips.