Add butter to a Dutch oven, preferably cast iron, set over medium-high heat. Add onion, green pepper and celery. Cook until onion is opaque.  Add garlic and cook until fragrant.  Add crawfish and cook until heated through.  Add cream and cream cheese and cook until heated through and cream cheese is melted.  Add your favorite Cajun seasoning to taste. Add pasta and heat through. Reduce heat to medium-low and cook until sauce is slightly thickened.  Cook pasta according to package instructions. Divide among four bowls and top with crawfish sauce.

Serve at once.