Viet Cajun Shrimp Boil Wrapped in Banana Leaves

Name: Viet-Cajun Shrimp Boil Wrapped in Banana Leaves
Ingredients: 2 pounds red skin baby potatoes; 5 tablespoons Cajun seasoning, plus more to taste; 2 pounds extra-large shell-on shrimp; 2 1/2 sticks (1 1/4 cups) unsalted butter; 10 cloves garlic, minced (about 1/4 cup); One 2-inch knob ginger, peeled and finely grated (about 1 1/2 tablespoons); 3 tablespoons fish sauce; Grated zest and juice of 2 large limes, plus lime wedges for serving; 1/2 teaspoon cayenne pepper (optional); 4 large banana leaves (each at least 34 inches long), thawed if frozen, rinsed; 3 ears yellow corn, husks removed, cobs cut crosswise into 1-inch-thick rounds; 1 pound andouille sausage, halved lengthwise and cut into 2-inch-long pieces; Toasted French bread, for serving; Hot sauce, for serving