1. Place the beans in a large bowl, add water to cover by 2 inches, and let stand overnight.

2. In a 2-quart saucepan, heat the oil over medium-high heat. Add the onions, bell peppers, and garlic; cook, stirring, until softened, about 3 minutes. Stir in the cumin until absorbed.

3. Add 3 1/2 cups of the water: bring to a boil. Add the drained beans, oregano, and bay leaf. Return to a boil. Reduce heat and simmer, uncovered, 2 to 2 1/2 hours, or until beans are very soft and mixture is thick. {If necessary, add the final 1/2 cup water during cooking time.} Stir in the salt and pepper. Discard the bay leaf.

4. Serve over rice.