I have seen people who saved the mirliton shells and stuff those with the shrimp mixture, but this is the fuss-free version of the dish. Mirlitons (also chayote pears) are pretty expensive in supermarkets, and it takes several to make a good casserole. In New Orleans, however, these vegetable pears grow on vines in every third backyard making them fairly easy to come by. In general, any recipe that calls for cooked eggplant or cooked winter squash can be prepared with mirlitons.
1. Boil whole mirlitons in water until tender, about 40 minutes. Drain mirlitons in a colander and let stand until cool enough to handle. Split the mirlitons in half lengthwise, remove the seeds, and scoop the pulp into a bowl. Using a potato masher or fork, mash the mirliton pulp.
2. In a skillet, melt 2 tablespoons butter over medium-high heat. Saute onions, celery bell pepper, garlic, half the parsley, and the green onions. Cook 3 minutes. Add 4 more tablespoons butter and the shrimp. Saute just until shrimp turn pink. Add ham.
3. Add the mashed mirliton pulp to the skillet and stir until heated through. Add the bread to the mixture and stir to blend. Slowly pour the eggs into the skillet while stirring quickly. Add salt and pepper to taste. Stir in remaining parsley.
4.Spoon mirliton mixture into a baking dish. Sprinkle with bread crumbs or cracker crumbs and dot with remaining butter. bake at 350 degrees F for 45 minutes or until dish is set and nicely browned.