Preheat oven 350F, convection.
Wash, dry, and slice tomatoes, not cutting through the end. Season them with salt, pepper, and fresh thyme leaves.
Place them on a baking pan, flatten slightly, and roast for an hour (middle rack). When roasted, brush tomatoes with olive oil. Let them cool to room temperature and refrigerate for at least 1 hour. Roasted tomatoes can be cooked in advance. Serve cold with sliced burrata, sprinkled with olive oil, and topped with fresh herbs. Fresh crusty bread is a must.