Preheat oven to 375˚. Cut tomatoes in half, scoop out seeds. Cut side up, lay on parchment paper covered baking pan with sides. Drizzle with olive oil. Sprinkle with garlic and thyme (if using). Roast for 40 minutes. Increase temperature to 400 ˚ and roast another 20 minutes. Turn off oven, leave tomatoes in oven for another 10 minutes. Remove from oven and allow tomatoes to cool. Puree in food processor to make a tomato pesto sauce for pasta.