Salmon en Croûte Recipe

Line a baking sheet with parchment paper. Season salmon fillets with salt and pepper. In a small bowl whisk together egg and milk to make an egg wash. Spread the sheet of puff pastry on a lightly floured surface. Dust pastry lightly with flour and, using a rolling pin, roll pastry into a 14-inch square. Using a sharp paring knife, trim the edges of the dough and cut dough into 4 equal squares. Place 1 tablespoon of the butter and then 1 of the salmon fillets in the center of 1 square and top with 1/4 of the leek and carrot mixture. Sprinkle with 1 teaspoon of the dill. Fold the edges of the pastry over the salmon and seal using a bit of egg wash along the edges of the pastry. Transfer the salmon packet to the prepared baking sheet with the seam side down. Repeat with remaining ingredients to form a total of 4 salmon packets. Cover the baking sheets with plastic wrap and refrigerate for 15 to 30 minutes to firm slightly. Meanwhile, preheat the oven to 400°F. Remove salmon packets from the refrigerator and remove the plastic wrap. Brush the top of each packet with egg wash. Bake until pastry is golden brown, about 20 to 22 minutes. Transfer salmon packets to individual plates, cut in half on a diagonal.