1. Bring a large pot of salted water to a boil. Add the pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta water before draining.
2. In a large saucepan, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1-2 minutes until fragrant and lightly golden.
3. Slowly pour in the milk, stirring continuously, and bring the mixture to a gentle simmer. This step is crucial to prevent the milk from curdling, a trick I learned while making sauces in Italian kitchens.
4. Gradually whisk in the Parmesan cheese until fully melted and the sauce is smooth. If the sauce is too thick, add a splash of the reserved pasta water to reach your desired consistency.
5. Season the sauce with salt, pepper, and lemon zest, enhancing the freshness and brightness of the dish.
6. Add the cooked pasta to the saucepan, tossing until the pasta is well-coated with the creamy sauce. Stir in the fresh parsley and a pinch of red pepper flakes if you’re using them.
7. Serve immediately, garnished with extra Parmesan cheese and parsley if desired.

Cooking this dish reminds me of the times when Nonna Rosa would teach me the importance of patience and attention to detail, especially when crafting the perfect sauce.