In a large 12-inch skillet, melt the butter over medium heat. Add the chopped onion, celery, and bell pepper. Cook, stirring occasionally, until softened and translucent, about 5 to 7 minutes.

Stir in the chopped parsley and minced garlic, and cook for another 2 minutes until fragrant. Transfer the mixture to a large bowl and let it cool completely.

While the vegetables cool, peel the boiled crabs to extract the meat. You should have about 1 1/2 pounds of lump and claw meat. Gently pick through to remove any shell fragments, and reserve 8 of the clean back shells. Rinse the reserved shells under warm water and set aside.

Preheat your oven to 350°F.

Add the crab meat to the cooled vegetable mixture and toss very gently to avoid breaking up the lumps.

In a small bowl, whisk together the mayonnaise, beaten egg, lemon juice, Worcestershire sauce, and hot sauce. Pour this over the crab mixture.

Sprinkle the Creole seasoning, Old Bay seasoning, and about three-quarters of the crushed crackers over the top. Gently fold everything together until just combined.

Add the Parmesan cheese and sliced green onions, and fold once more.

Press the crab mixture firmly into each reserved shell, mounding it high. Place the filled shells on a baking sheet.

Sprinkle the remaining crushed crackers over the tops, then dot each with a small pat of butter. Dust with paprika.

Bake the stuffed crabs uncovered for 30 minutes, until the tops are golden and the filling is hot throughout.

Remove from the oven and serve immediately.