https://www.redonline.co.uk/food/recipes/a500839/fish-pie-with-a-pastry-crust After a few minutes add the fish stock and cream and bring to the boil. The fish will shrink slightly as it cooks. Roll out the pastry to twice the size of the ovenproof dish. Making a puff pastry lid for your seafood pot pie is EASY. This means the pie is quicker to make and there is less danger of the fish becoming dry and overcooked. Next, press the bowl into the dough to make an indentation, and cut then around it. The fish wants to be cut into quite large bite-sized chunks (around 2″/5cm) this helps the fish stay together in the pie, so you get nice bites of fish rather than small flakes. Season and leave to one side. Cutting the fish. Simply roll out the pastry dough, and place an oven-safe bowl upside down on the dough.