Heat olive oil in a large skillet over medium-high heat. Add the Italian sausage and cook, breaking it up with a spoon, until browned.
Add the chopped onion and bell pepper to the skillet. Cook until softened, about 5-7 minutes.
Stir in the minced garlic and cook for 1 minute more until fragrant.
Add the broccoli florets and cherry tomatoes to the skillet. Season with Italian seasoning, red pepper flakes (if using), salt, and black pepper. Stir to combine.
Cover the skillet and cook for 5-8 minutes, or until the broccoli is tender-crisp and the tomatoes have softened.
Serve hot.
Notes
This dish is great on its own or served with a side of rice or crusty bread.