Preheat the oven to 400°F (200°C). Cut the top off the head of garlic, drizzle with olive oil, wrap in foil, and roast for 30-35 minutes until soft.

In a large pot, bring salted water to a boil. Add spaghetti and cook according to package instructions until al dente. Reserve 1 cup of pasta water, then drain the pasta.

In a skillet, heat olive oil over medium heat. Add minced garlic and sauté for 1 minute. Add diced tomatoes, basil, balsamic vinegar, salt, and pepper. Cook for 5-7 minutes until heated through.

Squeeze the roasted garlic cloves into the skillet with the tomato mixture. Add the drained pasta and toss to combine, adding reserved pasta water as needed to reach desired consistency.

Serve the pasta warm, topped with grated parmesan cheese and a drizzle of olive oil.