Take an ovenproof dish - I used a small pyrex dish that was enough for two servings - and line the bottom with rolled out shortcrust pastry. Line with greaseproof paper (I forgot this part but it makes it much easier) then fill with ceramic baking beans, or uncooked rice, and bake blind in the oven for 15 mins.
Meanwhile I poached some smoked haddock in milk
I also had a packet of salmon flakes (cooked) which I bought as they were reduced in the supermarket, and I decided to throw these in as well.
When the base of the pastry is cooked, spoon in the fish. I used the poaching milk as a basis for a small quantity of a white sauce which I poured over the top.
I've written before about my lattice pastry cutter; it's definitely easier to use with shop bought than homemade pastry! Roll out your pastry and roll the cutter over the top, then use your fingers to gently prise apart the lattice - you can see here I've done the top section but not the bottom section yet.
Place over the top of the pie and cut off any excess, then brush with milk or beaten egg.
Bake in the oven for 15-20 mins until the pastry on top is risen and golden brown. I think the lattice effect makes the pie look nice and it reduces the amount of pastry you need on top so it's even a little healthier!