How to Make It
In a 3- to 4-quart pan over medium-high heat, bring beans, tomatoes, 1/4 cup onion, and beer to a boil. Lower heat and cook, stirring occasionally, until most of the liquid is absorbed and remaining liquid is thick, 35 to 45 minutes. If a smooth consistency is desired, whirl in a blender or food processor until smooth. Stir in remaining 1/4 cup onion and the cilantro.