4 pounds medium mirlitons, peeled, cored, and cut into 3/4-inch pieces
2 tablespoons canola oil
3 tablespoons butter
1 1/2 cups tasso
1/2 cup chopped yellow onion
1/2 cup chopped green onion
1/2 cup chopped green bell pepper
1/4 cup chopped celery
1/4 cup minced garlic
1 pound peeled and deveined large fresh shrimp
3/4 cup fresh bread crumbs
1/2 cup heavy whipping cream
2 large eggs, lightly beaten
2 teaspoons chopped fresh thyme
2 teaspoons Creole seasoning
1/2 teaspoon ground black pepper
1/2 sleeve buttery round crackers, lightly crushed
3 tablespoons butter, melted
1 cup freshly grated mild Cheddar cheese
sliced green onion
Preheat oven to 425°. Line 2 rimmed baking sheets with parchment paper. Spray a 2-quart baking dish with cooking spray.
Place mirliton on prepared baking sheets, and coat with oil. Roast until lightly browned and tender, 25 to 30 minutes. Reduce oven temperature to 350°.
In a large Dutch oven, heat butter over medium-high heat. Add tasso; heat until browned, 3 to 5 minutes. Remove tasso from pot, and set aside.
Add yellow onion, green onion, bell pepper, celery, and garlic to Dutch oven; sauté until vegetables are softened, 3 to 5 minutes. Add roasted mirliton; crush about half of mirliton using a potato masher or fork. Cook over medium-high heat until mirliton has released its liquid and reduced slightly in volume, 13 to 15 minutes.
Remove from heat. Stir in shrimp, bread crumbs, cream, eggs, thyme, Creole seasoning, and pepper. Spoon into prepared baking dish, and loosely cover with foil.
Bake for 15 minutes.
In a small bowl, stir together crackers and melted butter. Sprinkle casserole with cracker mixture and cheese, and bake until cheese is melted and filling is bubbly, about 25 minutes more. Garnish with green onion, if desired.