Bring a large pot of generously salted water to a rolling boil. Add your pasta and cook according to package directions until al dente. Before draining, reserve about 1 cup of the starchy pasta water. Drain the pasta.

While the pasta is cooking, prepare the sauce. In a large bowl, combine the ricotta cheese, grated Parmesan cheese, lemon zest, lemon juice, minced garlic, and olive oil. Stir until well combined and creamy.

Add the drained pasta directly to the bowl with the ricotta mixture. Toss gently to coat the pasta evenly. Add about 1/4 cup of the reserved pasta water to help create a smooth, luscious sauce. Continue to toss until the sauce coats the pasta beautifully. If the sauce seems too thick, add a little more pasta water, a tablespoon at a time, until you reach your desired consistency.

Stir in the chopped fresh parsley and the optional red pepper flakes. Season generously with salt and freshly ground black pepper to taste. Remember that the pasta water and Parmesan cheese are salty, so taste before adding too much salt.

Serve immediately in warm bowls, garnished with extra Parmesan cheese and a sprinkle of fresh parsley.