Spray a large shallow baking dish with cooking oil. Lay the tomatoes in the dish and season with salt and pepper. Drizzle with the olive. Bake uncovered until tomatoes soften somewhat, about 25 minutes.
In a mini food processor, chop the garlic and basil together. Sprinkle the garlic/basil on top of the tomatoes. Cover with foil and bake until soft and lightly carmelized, another 25 minutes. Remove from oven and place in a food processor or blender. Pulse a few times, but leave the sauce chunky. Put in sauce pan to reheat and add cooked chicken if desired.
Serve over hot cooked pasta and top with freshly grated Parmesan.