How to Make It
In a large pot of boiling salted water, cook the pappardelle pasta until al dente. Drain the pappardelle thoroughly, reserving 1 cup of the pasta cooking water.
Meanwhile, in a large deep skillet, heat the olive oil. Add the scallions and sage and cook over high heat until lightly browned, 2 to 3 minutes. Add the spinach in large handfuls and cook, stirring, until wilted. Add the pasta, butter and ricotta and toss. Add 3/4 cup of the reserved pasta cooking water and the Parmigiano and season generously with salt and pepper. Cook over moderately low heat, tossing, until the sauce is thick and creamy, adding more of the pasta water as needed. Transfer the pappardelle to bowls and serve right away, with grated Parmigiano.