Mirliton and Gulf Shrimp Casserole

Name: Mirliton and Gulf Shrimp Casserole
Cook time: 1 h 50 min
Total time: 1 h 50 min
Cuisine: Cajun And Creole, Southern, American
Ingredients: 8 cups water; 2 tablespoons plus 1/4 teaspoon kosher salt, divided; 2 (10-ounce) mirlitons (chayote squash); 1 cup unsalted butter (8 ounces), plus more for drizzling (optional); 8 ounces smoked andouille sausage, halved lengthwise and cut into 1/2-inch-thick slices; 1 medium-size yellow onion, chopped (about 1 cup); 1 medium-size green bell pepper, chopped (about 1 cup); 2 medium celery stalks, chopped (about 1 cup); 2 tablespoons lower-sodium Creole seasoning; 4 small garlic cloves, finely chopped; 2 dried bay leaves; 1 (12-ounce) fresh French bread loaf, torn into small pieces (about 12 cups); 1 pound peeled and deveined raw small Gulf shrimp; 1 bunch scallions, sliced (about 1 cup); .5 cup unsalted chicken stock; .5 teaspoon black pepper; 2 ounces Parmesan cheese, shredded (about 1/2 cup)