In a Dutch oven over medium-high heat sweat onions, celery, bell peppers, and garlic for 10-12 minutes.

Add spices, stir well, and cook for 3-5 minutes.

Add flour, mix well to make a roux. After flour has been mixed thoroughly, add stock in increments of 1 cup while constantly mixing with roux. After adding all of the stock, begin adding half & half in the same process.

After all liquids have been added, reduce heat to low, and simmer sauce for 10-12 minutes.

Add crawfish tails, and simmer 3-5 minutes.

Fold in butter, one piece at a time. Add parsley, and green onions.

Serve over Rice