Step 1

Preheat oven to 350°. Toss tomatoes, thyme, garlic, and oil on a rimmed baking sheet to coat and season lightly with kosher salt. Spread out in a single layer and roast until tomatoes are bursting and lightly browned, 40–45 minutes; let cool.

Step 2

Arrange mozzarella on a platter and spoon warm tomato mixture with juices over; sprinkle with sea salt. Serve with olive-oil-toasted bread for soaking up all those extra juices.

Step 3

Do Ahead: Tomatoes can be roasted 1 day ahead. Cover and chill. Gently reheat before using.