Bring a large pot of salted water to a boil. Add the pasta and cook according to the package directions until al dente. In the last minute of the pasta’s cooking time, reserve 1/2 cup of the cooking water. Add the baby spinach leaves to the pot, stirring well and pushing them down so they are submerged in the water. After 1 minute, drain the pasta and spinach together and return them to the pot.
While the pasta cooks, combine the ricotta cheese, extra-virgin olive oil, finely grated Parmesan cheese, garlic, lemon zest, and lemon juice in a medium bowl. Season with about 1/4 teaspoon salt and a good pinch of freshly ground black pepper. Stir well until all the ingredients are thoroughly mixed and the sauce is smooth. Taste and adjust the seasoning if needed. I always make sure to taste the sauce here—sometimes an extra pinch of pepper makes all the difference.
Add the ricotta sauce (from Step 2) to the drained pasta and spinach (from Step 1) in the pot. Pour in some of the reserved pasta cooking water, stirring well to evenly coat the pasta and spinach in the creamy sauce. Add more pasta water as needed to achieve a smooth, creamy texture.
Serve the creamy ricotta spinach pasta immediately. Garnish each serving with extra grated or shaved Parmesan cheese, drizzle with more extra-virgin olive oil, and provide lemon wedges for squeezing if desired. For an added kick, I sometimes like to sprinkle on a pinch of red pepper flakes. Enjoy!