Pat the shrimp dry with paper towels.
Toss the shrimp with 2 teaspoons Cajun seasoning.
Heat olive oil and 1 tablespoon butter in a large skillet.
Cook the shrimp for 1 to 2 minutes per side.
Transfer the shrimp to a plate once pink and opaque.
Add the remaining butter, onion, and bell peppers to the skillet.
Cook for 5 to 6 minutes, stirring often.
Add the garlic and cook for 30 seconds.
Stir in the orzo, remaining Cajun seasoning, salt, and pepper.
Toast the orzo for 1 minute while stirring.
Pour in the chicken broth and bring it to a gentle simmer.
Cover and cook for 9 to 11 minutes, stirring often.
Lower the heat, then stir in the cream and parmesan.
Add the lemon juice and lemon zest.
Return the shrimp to the skillet.
Cook for 1 minute, just until warmed through.
Sprinkle with parsley, then serve warm.