Preheat the oven to 350°F. In a saucepan, cook and stir the cream cheese and 2 tablespoons of butter over low heat until they're melted and smooth.
In a large cast-iron or other ovenproof skillet, saute the onion, celery and green pepper in the remaining 2 tablespoons of butter until they're tender.
Stir in the shrimp, crabmeat, soup, rice, mushrooms, garlic salt, pepper sauce, cayenne and cream cheese mixture.
Combine the cheddar cheese and cracker crumbs, then sprinkle them over the top. Bake the skillet, uncovered, for 25 to 30 minutes or until the creamy seafood bake is bubbly.
Editor's Tip: To maximize the crab taste, remove any protective paper inside the can and pour the contents into a fine-mesh sieve that won't let the smallest shreds slip through. Let the brine drain away and rinse the meat under cold running water, flaking apart large chunks and removing any hard cartilage with your fingers before draining again.
