01 -
Bring a large pot of water to a boil over high heat. Add the pasta and cook according to package directions for al dente, stirring occasionally. Drain the pasta, reserving about 2 cups of the pasta cooking liquid.
02 -
While the pasta is boiling, heat a large heavy skillet over medium-high heat. Add the sausage and cook, stirring occasionally to break it into bite-size pieces. Transfer the cooked sausage to a plate, leaving the drippings in the skillet.
03 -
Add 1 tablespoon of butter to the skillet with the drippings. Add the onion and cook, scraping up browned bits in the skillet, until the onion is tender, about 3 minutes.
04 -
Add the cabbage, garlic, crushed red pepper, and salt. Toss to coat in the drippings and add about ¼ cup of the reserved pasta water. Cover with a lid and cook over medium heat for about 5-8 minutes, stirring occasionally and scraping the pan as needed.
05 -
When the cabbage is tender, add the cooked pasta and sausage to the skillet, along with 1 cup of the reserved pasta cooking liquid. Cook over medium heat, stirring constantly, until the liquid thickens to lightly coat the pasta, about 3 minutes.
06 -
Add the remaining 2 tablespoons of butter, Parmesan cheese, and lemon juice. Cook, stirring constantly, until the mixture becomes saucy, 1 to 2 minutes. Add a splash or two more of the reserved cooking liquid, if needed, to achieve the desired sauce consistency.
07 -
Taste the pasta and adjust salt if needed. Sprinkle with sliced basil and toss to combine. Serve immediately, with additional red pepper and Parmesan, if desired.