Cod Pocket Pie

Ingredients

• whole milk
• large garlic clove, smashed
• bay leaves
• large sprig fresh tarragon
• teaspoon kosher salt
• teaspoon white pepper
• ounces cod fillet
• tablespoons unsalted butter
• medium leek, cleaned, halved lengthwise, and thinly sliced
• small russet potato, peeled and finely diced
• tablespoons all-purpose flour
• dry white wine
• teaspoon freshly grated nutmeg
• teaspoon mustard powder
• tablespoon chopped fresh tarragon
• tablespoon chopped fresh dill
• vegetable oil, for frying
• ounces all-purpose flour
• teaspoons baking powder
• teaspoon kosher salt, plus extra for seasoning
• tablespoons shortening, cut in small pieces
• large egg