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