Arrange the tomatoes, thyme, garlic and olive oil on a rimmed baking sheet. Sprinkle with salt and pepper.
Roast at 300° for 35 minutes, or until the tomatoes are bursting and the skins are shriveling.
Remove from oven and allow to cool for several minutes.
Peeling the tomatoes is optional (and tedious).
Serve as a side dish.
Or for sauce, remove the thyme leaves and discard the woody stems. Place all ingredients into a blender or food processor and puree until smooth. (makes approximately 2 cups of sauce)