Clean the shrimp and season with 2 tablespoons Cajun spice. Drizzle the flour over the shrimp and toss in a bowl to make sure each shrimp is covered in flour.
In a deep skillet add butter and olive oil and heat over high heat. Add shrimp and cook on each side about 2 minutes until crisp. Remove shrimp from skillet and set aside.
In the same skillet add chicken broth and heavy cream. Season with additional Cajun spice if preferred. Cook until sauce thickens a bit from the heavy cream, then add Parmesan cheese and whisk. Add fettuccine and shrimp to the sauce and toss.