Butternut squash, cherry tomatoes, merguez sausage, and shallots are roasted together to make a spectacular sweet-and-savory sauce. Don't forget to deglaze the sheet pan with pasta water for even more flavor!
Preheat oven to 450 degrees with rack in top third. On a rimmed baking sheet, toss squash, tomatoes, sausage, and shallots with oil and vinegar. Season with salt and pepper. Roast until squash is golden and sausage is cooked through, 30 to 35 minutes. Transfer sausage to a cutting board; let cool slightly, then slice into 1-inch pieces.
Cook pasta in a large pot of salted boiling water until al dente. Drain, reserving 1 cup water. Return pasta to pot with sausage, squash, and basil. Add 1/2 cup pasta water to sheet and scrape up browned bits; add to pot. Toss to coat, adding more pasta water as needed; season with salt and pepper. Set oven to broil and transfer pasta mixture to sheet. Top with cheese; broil until melted and browned in spots, 2 minutes. Top with basil leaves; serve.