Preparation Heat oil and butter in a large heavy pot over medium heat. Add squash and sage and cook, stirring occasionally, until squash begins to brown, about 2 minutes. Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain pasta, reserving 2 cups pasta cooking liquid. Add pasta and 1/2 cup pasta cooking liquid to squash and stir to coat. Cook over medium heat, stirring, adding more cooking liquid as needed, until sauce coats pasta. Stir in 1/2 cup Parmesan. Divide pasta among bowls; top with more Parmesan.
Preparation Heat oil and butter in a large heavy pot over medium heat. Add squash and sage and cook, stirring occasionally, until squash begins to brown, about 2 minutes. Meanwhile, cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain pasta, reserving 2 cups pasta cooking liquid. Add pasta and 1/2 cup pasta cooking liquid to squash and stir to coat. Cook over medium heat, stirring, adding more cooking liquid as needed, until sauce coats pasta. Stir in 1/2 cup Parmesan. Divide pasta among bowls; top with more Parmesan.