Ingredients

• 1 pound casarecce or other short pasta
• Kosher salt
• 1/4 cup olive oil
• 1 large onion, thinly sliced
• 1 pound spicy Italian sausage, casings removed
• 1 1/4 pounds radicchio, cored, coarsely chopped (about 7 cups)
• 1/2 cup thinly sliced drained oil-packed sun-dried tomatoes
• Freshly ground black pepper

Instructions

1. Cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain pasta, reserving 3/4 cup pasta cooking liquid; return pasta to pot.
2. Meanwhile, heat oil in a medium skillet over medium-high. Add onion and 1/4 tsp. salt and cook, stirring occasionally, until tender, about 5 minutes (do not brown). Add sausage and cook, stirring occasionally and breaking up sausage into small bits with a wooden spoon, until sausage is mostly cooked through, about 5 minutes. Add radicchio and 2 Tbsp. water. Cook, covered, until sausage is cooked through and radicchio is wilted, 3–5 minutes more.
3. Add tomatoes, sausage mixture, and 1/2 cup pasta cooking liquid to pot with pasta. Season with salt and pepper, toss to coat, and add remaining 1/4 cup pasta cooking liquid, if needed. Divide among serving plates and top with pepper.