Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente, usually about 8-10 minutes. Reserve ½ cup pasta water and set aside.

In a large pan over high heat, add 2 tablespoons of olive oil. Add diced zucchini and cook for 3 minutes without stirring. Stir in more oil if needed, then reduce heat and cook for another 5 minutes until tender.

Mix in minced garlic, lemon zest, salt, and black pepper to sautéed zucchini. Cover and cook for approximately 7 minutes, stirring occasionally.

Add lemon juice, cooked spaghetti, grated Parmesan, and reserved pasta water to the pan. Stir together over medium heat to develop a creamy sauce.

Serve with a sprinkle of fresh basil, chili flakes, and extra Parmesan if desired. Drizzle olive oil over each serving.