Preheat oven to 225 degrees F. Arrange tomatoes in a single layer, cut side up, on large baking sheet lined with foil or parchment paper. In a small bowl mix together garlic, basil and oil, and brush over tomatoes. Sprinkle with salt and pepper. Bake 2 hours or until tomatoes soften and shrivel slightly, and edges have very lightly browned. Serve warm or at room temperature.