Italian Sausage Pasta with Vegetables

olive oil

Italian sausages (, casings removed, sliced)

small onion (, very finely chopped)

garlic cloves (, finely minced)

Cajun seasoning

bell pepper (, very finely chopped)

tomatoes (, chopped, or 15 cherry tomatoes, each sliced in half)

mushrooms (, finely sliced)

red wine

penne pasta ((for gluten-free, use gluten-free brown rice penne))

Parmesan cheese (, shredded)