The Easy Banana Bread Casserole You Can Make Ahead

Name: The Easy Banana Bread Casserole You Can Make Ahead
Ingredients: Cooking spray; 2 (1-pound) loaves banana bread , cut into 1-inch cubes (about 10 cups ); 6 large eggs; 2 1/2 cups half and half; 1/4 cup packed light brown sugar; 1 tablespoon vanilla extract; 1 teaspoon kosher salt; 4 tablespoons salted butter , melted and divided; 3/4 teaspoon plus 1/8 teaspoon ground cinnamon , divided; 6 tablespoons chopped toasted pecans , divided; 1 tablespoon powdered sugar , for garnish, optional; 1 banana , sliced, for serving, optional