6 oz penne
1 tbsp evoo
2 scallions, green and white parts, thinly sliced
1/2 tbsp sage, finely chopped
5 oz baby spinach
1 tbsp unsalted butter, cut into cubes
2/3 cup fresh ricotta cheese
1/4 cup freshly grated Parmigiano-Reggiano cheese, plus more for serving
Cook the pasta in a large pot of boiling salted water, until nearly al dente (drain the pasta 1 minute short of al dente). Drain the pasta thoroughly, reserving 1/2 cup of the pasta cooking water.
Meanwhile, in a large deep skillet, heat the evoo. Add the scallions and sage and cook over moderately-high heat until lightly browned and fragrant, 2 to 3 minutes. Add the spinach and cook, stirring, until wilted. Add the pasta, butter and ricotta and toss until combined. Add 1/4 cup of the reserved pasta cooking water and the parm-reg. Season generously with s&p. Cook over moderately low heat, tossing, until the sauce is thick and creamy, adding more of the pasta water as needed. Transfer the pasta to bowls and serve right away, with additional grated parm-reg.