Preheat the oven to 200°C.

Gently poach the trout in the milk with the shallot, peppercorns and prawns, for approximately 10-15 minutes until just cooked. Remove the fish, prawns, shallots and peppercorns from the milk but do not throw the milk away.

Melt 3 tablespoons of butter and whisk in the flour to make a base for a white sauce. Slowly add the poaching liquid to the butter mixture, whisking continuously until the sauce becomes thick and smooth. If your sauce is too thick, add a dash more milk to achieve the desired consistency. Add a generous grinding of NOMU Seafood & Fish Grinder and Salt and Pepper to taste.

Shred the fish and add it back into the white sauce with the watercress and prawns. Place the fish mixture into your pie dish.

Boil the potatoes in salted water until soft when pricked with a fork, drain well and place back into the pot. Using a ricer or potato masher, crush the potatoes until they become soft and fluffy. Heat the cream and remaining 2 tablespoons of butter together, and stir into the potatoes. Check the seasoning and add Salt and Pepper to taste. Cover the fish mixture with the mashed potato and place in a hot oven for 15-20 minutes until golden brown and bubbling.