Tuscans are commonly known as mangiafagioli, or bean eaters, and when you simmer cannellini beans on top of the stove and then finish them in the oven with a fresh tomato ragù, you'll understand why. The dish is saucy and comforting—have plenty of good bread on hand—with welcome bursts of acidity from the extra tomatoes scattered on top of the casserole. Grape tomatoes tend to have a sweeter, more concentrated flavor than cherry tomatoes.
•To quick-soak beans, cover with water by 2 inches in a 5-to 6-quart heavy pot and bring to a boil, then boil 1 minute. Remove from heat and cover, then soak 1 hour. Drain, discarding water.
•Beans can be cooked 1 day ahead. Cool in liquid, then chill.
•Tomato ragù can be made 1 day ahead and chilled.
•Dish can be assembled (but not baked) 8 hours ahead and chilled.
