1. Heat 2 tbsp oil in a large nonstick skillet over medium heat.

2. Add sausage and cook, breaking up the meat using a wood spoon, until browned, about 5 minutes.

3. Scrape the mixture into a medium bowl.

4. Add remaining 2 tbsp oil, broccoli, peppers, and garlic to the skillet and season with salt and pepper.

5. Cook, stirring often, until softened and beginning to brown, about 8 minutes.

6. Cook pasta in a large pot of boiling salted water until al dente.

7. Reserve 1 cup cooking water and drain pasta.

8. Return pasta and reserved water to pot over low heat.

9. Add broccoli mixture, cooked sausage (with juices), 1/2 cup Parmesan, lemon juice, and red pepper flakes.

10. Stir vigorously until liquid is slightly thickened and sauce, about 2 minutes.