Slice the smoked or Italian sausage into bite-sized pieces. Heat olive oil in a large skillet over medium heat. Add sausage and sauté for 5-7 minutes until browned. Remove and set aside.

In the same skillet, add chopped yellow onion. Sauté for 3-4 minutes until translucent.

Add sliced bell peppers to the onions. Sauté for about 5 minutes until slightly tender.

Sprinkle in minced garlic and stir for 30 seconds until fragrant.

Pour in crushed tomatoes, season with salt and black pepper, and let simmer on low heat for 10-15 minutes.

In a pot, bring salted water to a boil. Cook penne pasta according to package instructions until al dente, about 10-12 minutes. Reserve 1/4 cup pasta water, then drain.

Add drained penne pasta to the skillet with the sauce and sausage. Toss gently, using reserved pasta water to adjust the sauce consistency. Cook for an additional minute.

Serve the pasta on plates, garnished with chopped parsley.