Brush tomatoes with remaining tablespoon oil and season with salt and pepper. Wrap garlic tightly in foil and roast tomatoes and garlic in pan in middle of oven about 20 minutes, or until tomatoes are lightly browned and garlic is tender when pierced with a knife. Peel garlic and in a blender purée with tomatoes and vinegar until smooth, adding some water if coulis is too thick. Season coulis with salt and pepper. Coulis may be made 1 day ahead and chilled, covered.