1 1/2 pounds small zucchini, halved lengthwise and sliced 1/2 inch thick
Salt and freshly ground pepper
4 tablespoons unsalted butter
3/4 cup freshly grated Parmesan cheese (about 2 ounces)
1/4 cup plus 2 tablespoons basil
Cook the pasta in a large pot of boiling salted water until al dente. Drain, reserving 1 cup of the cooking water.
Meanwhile, heat 1/4 cup of the olive oil in each of 2 large skillets. Add half of the zucchini to each skillet, season with salt and pepper and cook over high heat, stirring occasionally, until lightly browned, about 5 minutes.
Return the pasta to the pot and add the butter and zucchini along with any olive oil in the skillets. Add 1/2 cup of the reserved pasta cooking water and half of the Parmesan and season with salt and pepper. Cook over moderate heat, stirring, until the liquid is creamy and slightly absorbed, 1 to 2 minutes. Add more of the pasta cooking water if the pasta is dry. Stir in half of the basil and transfer the pasta to a large platter. Sprinkle with the remaining basil and Parmesan and serve immediately.