Habichuelas Guisadas (stewed Beans)

Ingredients
2 cups of dry pinto , cranberry, or red kidney beans
1 tablespoon of olive oil
1 pinch of oregano
1 bell pepper , chopped
1 small red onion cut into four quarters
2 cloves of garlic , crushed
1 cup of diced auyama (West Indies pumpkin)
1 cup of tomato sauce
Leaves from a celery stalk , chopped (optional)
4 sprigs of thyme (optional)
½ teaspoon of chopped fresh cilantro
1 teaspoon of salt (or more, to taste)

Preparation
Soak the beans overnight.
Remove the beans from the soaking water and boil in fresh water until they are very soft (may take up to an hour, or about 20 minutes in a pressure cooker.
Separate the beans from the boiling water. Reserve both.
In a pot heat the oil over medium heat.
Add oregano, bell pepper, onion, garlic, auyama, tomato sauce, celery, thyme and cilantro. Cook and stir for half a minute.
Add the beans and simmer for two minutes.
Add 6 cups of the water in which the beans boiled (complete with fresh water if necessary).
Lightly mashed the beans with a potato masher to break them out of the skin.
Cook until it reaches a creamy consistency.
Season with salt to taste.
Serve with arroz blanco, a side dish (or salad) and meat.