• One double-batch Rich Pie Dough

Curried Fish Filling

• 1¼ cups fresh white bread crumbs (crustless fresh French or Italian bread, diced and ground in the food processor)
• 1 cup warm milk
• ¼ cup vegetable oil, such as canola
• 1 large onion, 10 to 12 ounces (257 to 350 grams), peeled and chopped
• 3 large garlic cloves, peeled and grated on a Microplane
• 1½ pounds (700 grams) firm-fleshed fish, such as cod or halibut, cut into ½-inch (1-cm) dice
• 2 teaspoons salt
• 2½ tablespoons best-quality curry powder (more if you like a strong curry flavor)
• 1 tablespoon ground turmeric
• ½ teaspoon ground cloves
• 1 cup milk
• 1 tablespoon sugar
• 1 tablespoon cider vinegar
• ⅔ cup golden raisins
• ⅔ cup mango chutney, chopped if chunky
• ⅔ cup (about 3 ounces/75 grams) slivered almonds, toasted and coarsely chopped
• 5 large eggs

Custard Topping

• 1½ cups milk, heated to about 120°F (50°C)
• 3 large eggs
• 8 to 10 fresh lemon, lime, or bay leaves, rinsed well to remove any sprays
• One 3- to 3½-quart oval enameled cast-iron gratin dish or a 9 × 13 × 2-inch (23 × 33 × 5-cm) glass baking dish, buttered

1. Place the dough on a floured work surface and shape it into a square. Flour the dough and press it out, then roll it, according to the instructions. If you’re using a gratin dish, measure the width and depth of the pan. The width of the dough should be the same width as the pan, plus 2 times its depth, plus inches (4 cm); calculate the length the same way. For a 9 × 13-inch (23 × 33-cm) pan, the dough should be about 15 × 19 inches (38 × 48 cm.)
2. Fold the dough in half lengthwise and transfer it to the pan, lining up the fold with the middle of the pan. Unfold the dough into the pan and press it well into the bottom and sides. Trim away all but ½ inch (1 cm) of the excess dough at the rim of the pan and let it hang over the edge for the time being.
3. For the filling, soak the bread crumbs in the warm milk and set aside.
4. Combine the oil, onion, and garlic in a wide sauté pan and place over medium heat. When the onion starts to sizzle, reduce the heat and let the onion and garlic cook until soft and just beginning to color slightly, about 15 minutes.
5. While the onion is cooking, set a rack in the lowest level of the oven and preheat to 375°F (190°C).
6. Add the fish to the pan in an even layer and sprinkle with the salt, curry powder, turmeric, and cloves. Toss or stir the fish and seasonings with the onion and garlic just until the fish is evenly coated. Add the milk and increase the heat to medium. When the liquid starts to simmer, regulate the heat until it just simmers gently and cook until the fish may be flaked easily with a fork, about 15 minutes.
7. Remove the pan from the heat and use 2 forks to shred the fish into large flakes. Stir in the sugar, vinegar, raisins, chutney, almonds, and the soaked bread crumbs. Taste for seasoning and adjust with salt, sugar, and vinegar. The filling should be slightly over-salted, with a subtle sweetness and a strong hint of acidity from the vinegar.
8. Whisk the eggs in a bowl until very liquid and use a large rubber spatula to stir them into the fish mixture. Scrape the filling into the crust and trim away the excess dough even with the rim of the pan.
9. Bake the pie until the filling is set and the dough is baked through and golden, 35 to 40 minutes.
10. While the pie is baking, whisk together the milk and eggs for the custard and have it ready on the stove.
11. When the pie is done, remove it from the oven and evenly pour the custard over it. Scatter the leaves over the custard and return the pie to the oven to bake until the custard is set, about 10 minutes. Cool the pie on a rack.