Heat large pot of salted water to boiling on stove, then cook pasta according to package instructions. 

Meanwhile, remove tails from shrimp and discard; pat shrimp dry with paper towel. Place shrimp in medium bowl and sprinkle with 1 teaspoon Cajun seasoning; toss until all sides of shrimp are coated with seasoning.

Heat 1 tablespoon butter in Dutch oven over medium heat. Add shrimp and cook 2 to 3 minutes or until shrimp start to turn pink, stirring frequently. Transfer shrimp to large plate and set aside. Shrimp do not need to be fully cooked at this point.

Add remaining 1 tablespoon of butter to pot. Add mushrooms and cook 3 to 4 minutes over medium heat or until light golden brown, stirring occasionally. 

Add zucchini to pot and cook 4 to 6 minutes longer or until zucchini is tender, stirring occasionally. Transfer mushrooms and zucchini to plate with shrimp.  

Return pot to heat and add sundried tomatoes and their oil, garlic and shallot to pot.  Cook 1 minute, stirring constantly. 

Add cream, stock, lemon juice, salt, pepper and remaining 1-1/2 teaspoons Cajun seasoning. Heat to boiling over medium heat, then reduce heat to medium-low and cook 5 to 6 minutes or until mixture is thickened to a thin sauce consistency, stirring frequently. 

Reserve 1/4 cup pasta cooking water, then drain pasta. Add pasta and reserved cooking water to pot with sauce. 

Add shrimp, mushrooms and zucchini to pot and cook over medium-low heat 1 to 2 minutes or until shrimp is opaque throughout and internal temperature reaches 145 degrees F, stirring and tossing to combine everything.

Serve garnished with Parmesan cheese, and parsley, if desired.