Step 1

Place a rack in middle of oven; preheat to 350°. Toss tomatoes, garlic, rosemary, oil, coriander seeds, and salt in a shallow 2-qt. baking dish to combine.

Step 2

Turn garlic cut side down, then roast tomatoes, tossing 2 or 3 times, until golden brown and very tender, 40–50 minutes. Let cool slightly, then add vinegar and toss to coat.