Preheat a grill or grill pan and spray with cooking spray. Season fish with salt and pepper and place fish on grill; cook for 5 to 6 minutes on each side or until flakey.
Meanwhile, make sauce: melt butter in a large skillet over medium-high heat. Stir in green onions, garlic, and Creole seasoning. Add cream and lower heat to medium. Stir until mixture is reduced by half, about 5 minutes. Add crawfish and stir for about 30 seconds or until just heated through. Season with salt and pepper, to taste.
To serve, plate fish and spoon Crawfish Bayou Sauce over center of fish. Garnish with parsley.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.