Preparation Purée half of beans in food processor with 1 cup water until smooth. Tie cilantro into a tight bundle with string. Cook onion and garlic in olive oil in a 5- to 6-quart heavy pot over moderate heat, stirring occasionally, until onion is softeneed but not brown, about 8 minutes. Add tomato paste, vinegar, and 1 cup water, then bring to a boil and cook, stirring, 2 minutes. Add puréed and whole beans, Cubanelle pepper halves, cilantro, bay leaves, salt, oregano, pepper, and remaining 2 cups water, then simmer, uncovered, stirring occasionally, 1 1/2 hours (mixture will reduce and thicken). Remove and discard Cubanelle pepper halves, cilantro, and bay leaves, then serve. Cooks' note:Beans can be puréed and cooled completely, uncovered, then chilled, covered, 3 days.
Preparation Purée half of beans in food processor with 1 cup water until smooth. Tie cilantro into a tight bundle with string. Cook onion and garlic in olive oil in a 5- to 6-quart heavy pot over moderate heat, stirring occasionally, until onion is softeneed but not brown, about 8 minutes. Add tomato paste, vinegar, and 1 cup water, then bring to a boil and cook, stirring, 2 minutes. Add puréed and whole beans, Cubanelle pepper halves, cilantro, bay leaves, salt, oregano, pepper, and remaining 2 cups water, then simmer, uncovered, stirring occasionally, 1 1/2 hours (mixture will reduce and thicken). Remove and discard Cubanelle pepper halves, cilantro, and bay leaves, then serve. Cooks' note:Beans can be puréed and cooled completely, uncovered, then chilled, covered, 3 days.