1 kg cooked white fish (eg, cod)
1 onion, chopped
2 tbsps plain flour
300ml milk
400g can of chopped tomatoes
100g grated cheese
200g any veg (I usually use frozen, but fresh is OK if you cut it into small pieces)
lemon juice
black pepper
Approximately 4 kg potatoes, mashed

Flake the cooked fish so that it will go into the sauce easily when needed.

Melt the butter and fry the onion until soft.

Add the flour and mix well. Remove from the heat and slowly add the milk, just a little at a time, stirring well to avoid lumps. Return to the heat, stir until boiling and cook for three minutes, stirring all of the time.

Add cheese, tomatoes, pepper and a squirt of lemon juice. Stir well. Add vegetables and stir into mixture. Bring back to the boil and cook for about 5 more minutes, stirring constantly.

Divide mixture into portions.

Cover with the mashed potato.

Cook at 200°C for approx 30 mins (until heated right through and probably slightly brown on top).