Drain the beans, put in a large pot, and add the garlic and water to cover by 1 inch. Bring to a boil, then lower the heat to a simmer and cook, stirring occasionally, until the beans are soft, about 1½ hours; add more water if necessary to keep the beans covered.

Add the tomatoes (if using canned tomatoes, break them up with your hands as you add them) and a large pinch, or two or three, of salt and pepper. Cook for another 10 or 15 minutes, until the tomatoes have completely broken down. Serve drizzled with olive oil.