The colors and flavors of autumn star in this stand-out pasta dish.
The key to success with this recipe lies in the simultaneous cooking of the three basic components; make sure to have everything prepped before you start. In the time it takes to bring the water to a boil and cook the pasta, you should be able to cook the squash in one skillet and the remaining ingredients in another. Then, once you drain the pasta, everything gets combined in one pan to quickly finish the dish.
Melt the butter in a large skillet over medium-high heat. Add the butternut and cook, stirring frequently, until the squash is just tender, 5 to 8 minutes. Add the sage and thyme, and season to taste with salt and pepper. Keep warm.
Meanwhile, bring a large pot of water to a boil and add a generous tablespoon of salt. Add the pasta and cook until it's al dente (firm-tender). Reserve 1 cup of the pasta cooking liquid and drain the pasta.
While the pasta is cooking, heat the olive oil in another very large skillet over medium heat. Add the pancetta and red pepper flakes, and cook, stirring frequently, until the pancetta is half-cooked, about 4 minutes. Add the shallots and continue cooking until they're soft and the pancetta is almost fully cooked, 3 to 4 minutes, stirring frequently. Add the garlic and cook another 2 minutes, stirring constantly to avoid burning the garlic. Pour the wine into the skillet and add the spinach, stirring until it's wilted, about 2 minutes.
Transfer the pasta to the skillet and add 1/2 cup of the reserved pasta liquid. Toss to coat the linguine (tongs are useful for this step); add more pasta liquid if the mixture seems dry. Add half of the Parmesan and stir until it melts and the pasta has absorbed most of the liquids in the pan. Add the reserved butternut and toss gently to combine.
Transfer the pasta to a large heated platter and sprinkle with the remaining Parmesan. Serve hot.