Toss shrimp with salt, pepper, Cajun seasoning, and Oregano, coat well. Heat a large skillet over medium-high heat and drizzle with olive oil.
Add shrimp; cook for 2 minutes, flip over, and cook another minute or two. Then remove to a plate and set aside.
In the same pan, add a little more olive oil, add sausage, and brown for about 4 – 5 minutes. Remove to plate, set aside.
Cook pasta in salted boiling water until al dente.
Lower heat to medium, add more olive oil to the pan, then add onion, red bell pepper, Cajun seasoning, brown sugar, and a pinch of salt. Sauté until softened, scraping up any browned bits.
Add garlic; cook until fragrant, about 30 seconds.
Add crushed tomatoes, chicken broth, and heavy cream. Bring to a simmer, stirring to scrape up any brown bits from the bottom of the pan, and simmer a couple of minutes.
Once simmering, add Parmesan, stir into sauce. Then add cooked pasta and sausage; stir to combine and heat through, 2 – 3 minutes. Season with salt and pepper to taste, then lastly, add shrimp.
Serve with chopped parsley.