Two simple vegetarian additions turn simple one-pot pasta into a vibrant main dish. You can customize the ingredients to suit your taste. You can use any kind of noodle you prefer or switch up the greens with chopped kale, escarole or chard instead of spinach.
Put 2 tablespoons of the butter in a large pot over medium heat. When it is hot, add the onion and cook, stirring occasionally, until it softens, about 3 minutes. Add the pasta, raise the heat a bit, and cook, stirring constantly, until it's glossy and smells toasty, about a minute. Add a little salt and pepper, then the wine, and stir.2.
Let the liquid bubble away. Begin to add water, 1/2 cup at a time, stirring after each addition. When the liquid is just about absorbed, add more. The noodles should be neither soupy nor dry. Keep the heat at medium to medium-high, stir frequently, and repeat as necessary.3.
Begin tasting the pasta 10 minutes after you added it. When the pasta is just getting tender but still is too firm to eat, add the spinach and ricotta. (It could take as long as 15 minutes to reach this stage.) When the pasta is ready and the spinach softens, stir in the remaining butter and the Parmesan, adding a little more water if necessary to coat the noodles in sauce. Taste and adjust the seasoning. Serve right away, passing more Parmesan at the table.