Mix the shrimp in a bowl with the cajun seasoning. Set aside.
Heat the olive oil in a large skillet or saute pan to medium high heat.
Add the smoked sausage in an even layer and cook until browned (about 3-4 minutes per side). Remove the browned sausage from the pan and set aside. Be sure to leave the drippings in the pan and do not wash it.
In the same pan that you cooked the sausage, add the seasoned shrimp in an even layer. Saute for 2 minutes per side. During this step, the goal is to get a browned sear on the outside of the shrimp. Remove the cooked shrimp and set aside. It will continue to cook as it rests. Do not wash the pan.
Add the garlic, shallots and peppers to the pan that you cooked the shrimp and sausage in. Saute until the onions are translucent (about 3-4 minutes).
Pour in the chicken broth and deglaze the pan if needed (this means scrape up any bits that might be stuck to the bottom of the pan).
Turn the heat to medium low. Add heavy cream and parmesan cheese. Mix to create a sauce. For a spicy kick, add the cayenne pepper to this step.
Return the cooked shrimp, sausage, and pasta to the pan. Stir to incorporate. For photos, please reserve some seared shrimp and sausage for the top so that the components are visible.
Top with chopped parsley and serve.