Preheat oven to 400°F (205°C) and line a sheet pan with parchment paper or foil.
In a large bowl, combine sliced sausage, baby potatoes, bell pepper, zucchini, and red onion.
Add olive oil, garlic powder, Italian seasoning, paprika, salt, and black pepper; toss to coat evenly.
Spread the mixture evenly on the prepared sheet pan.
Bake for 25–30 minutes, flipping the ingredients halfway through for even roasting.
If desired, sprinkle Parmesan cheese on top and broil for 2 minutes until melted and golden.
Serve hot as is or over rice or pasta.