Begin by bringing a large pot of salted water to a rolling boil. Add the linguine pasta and cook according to package directions for about 9-11 minutes until al dente. Reserve about a cup of the pasta water, then drain the rest and set the pasta aside.

While the pasta cooks, take your raw shrimp and season them with garlic powder, onion powder, Cajun seasoning, and paprika. Melt butter in a large skillet over medium heat. Add the seasoned shrimp and sauté for 2-3 minutes per side until they turn pink and opaque. Remove the shrimp from the skillet and set aside.

In the same skillet, add more butter if needed and introduce the smoked sausage. Brown the sausage slices for 1-2 minutes on each side until they have a nice golden color. Transfer the sausage to the plate with the shrimp.

Add diced onions, green bell pepper, mushrooms, and minced garlic to the skillet. Sauté the vegetables for about 5 minutes or until they become soft and fragrant.

Pour in lemon juice, crushed tomatoes, and heavy whipping cream into the skillet. Stir well to combine and season with additional Cajun seasoning. Allow the mixture to simmer for 10-12 minutes, or until the sauce thickens nicely.

Toss the drained linguine into the sauce, gently folding in the shrimp and sausage until everything is evenly coated. If the sauce seems too thick, add a splash of the reserved pasta water to achieve your desired consistency. Serve warm, garnished with optional Parmesan cheese if you like.