Place tomatoes, vinegar, garlic and basil in a blender and blend until smooth. Slowly add the olive oil until emulsified. Season with salt and pepper to taste. Preheat grill. Brush the vegetables with olive oil and season with salt and pepper to taste. Grill until cooked through. Arrange on a platter and drizzle with tomato vinaigrette. Turn each slice over, sprinkle with parsley and grill an additional 20 seconds.