Cajun Shrimp with Tomato Alfredo Pasta

dry pasta (such as fettuccine)

large shrimp (uncooked, shells removed)

cajun seasoning

olive oil

butter

small onion (chopped)

garlic (minced)

can diced tomatoes

heavy cream

Parmesan cheese (grated)

salt (or to taste)

pepper (or to taste)

leaves fresh basil (chopped for garnish)