Heat oil in a large saucepan and saute sausage on all sides until golden brown, about 6-10 minutes; set aside.
Add onion, garlic, and bell peppers and saute until onions are soft, about 3 minutes.
Stir in basil, parsley, thyme, and oregano and cook until fragrant, about one minute.
Add tomatoes, vegetable broth, tomato paste, sugar, and salt.
Bring the sauce to a boil, cover, and simmer until it begins to thicken, about 5 minutes. Add the sausages, cayenne pepper, and nutritional yeast flakes to the sauce and cook for another 5 minutes on low heat.
Serve sausage and peppers over pasta.