First, prepare your mashed potatoes. How much you make will depend on the size of the dish you're making the pie in and how much you love mashed potatoes. I usually cook about 1.5 kg potatoes and mash with 50 grams of butter and a generous splash of milk until they're creamy. Leave to cool before topping the pie.
Heat butter in a saucepan over a medium high heat and pop the kettle on to make the fish stock.
When the butter is bubbling, stir in the flour and cook for one minute, stirring constantly.
Remove the pan from the heat and stir in the fish stock and cream. Whisk until thoroughly combined and return to the heat, reheating gently until the mixture is thick and smooth. Set aside.
Cut your fish into pieces and add straight to the cream mixture along with the boiled eggs, frozen peas and fresh dill. Stir gently to combine.
Place the mixture into a deep 9 x 6-inch casserole dish, or, let's face it, any dish you fancy. Want a deep fish pie use a smaller dish. Want a thin layer of fish, use a larger dish.
Spoon over the cooled mashed potatoes and, using the tines of a fork, spread evenly over the cooled fish mixture. Dot with butter.
You can, at this stage, cover and refrigerate until needed or bake immediately in a preheated 200 C oven for 30-35 minutes until the top is golden and the cream mixture is bubbling a bit at the sides.
Serve with a green vegetable so you feel like you're offsetting the calorific cream content with something a bit more healthy. Or not. Enjoy!
Leftovers reheat very well. Simply cover the leftovers in aluminium foil and reheat for 30 minutes.