1. Melt butter in medium saucepan over low heat. 2. Add flour until thickened. 3. Cook this roux over low heat, stirring often for 10 minutes. 4. Be sure not to brown your roux, it should be a white roux. 5. Add celery, stir and cook for 3 minutes. 6. Add cheese, whipping cream, milk, parsley and seasonings. 7. Cook until cheese is melted and sauce thickens. 8. Fold in crabmeat and transfer to casserole dish. 9. Brown in oven and serve.