1. Bring a large pot of salted water to boil. Add the pasta and cook until al dente, about 10 minutes (check the package instructions for exact timing). Reserve 3 cups of the pasta cooking water, then drain the pasta and set aside.

2. In a large bowl, mix together the ricotta, Parmesan, lemon zest, and lemon juice. Add 2 cups of the reserved pasta cooking water and mix to thoroughly combine (reserve the remaining pasta cooking water for the next step).

3. Transfer the drained pasta and sauce to a large skillet, stir to combine, and place over medium heat. Gradually add more pasta cooking water, ¼ cup at a time, until everything is combined and creamy (you may not use all of the water). Taste and season with salt and pepper.

4. Garnish with the chopped chives and serve!