Ingredients

Method

  1. Heat the oven to 180C.
  2. Place potatoes in a saucepan, cover with water, bring to the boil and then simmer until soft.
  3. When cooked, drain thoroughly and mash with a splash of milk and a knob of butter. Season with ground black pepper.
  4. Put 25g butter, 25g plain flour and 4 finely sliced spring onions in another pan and heat gently until the butter has melted, stirring regularly. Cook for 1-2 mins.
  5. Gradually whisk in 400ml milk using a whisk. Add thyme and bring to the boil, stirring to avoid any lumps. Cook for 3-4 mins until thickened.
  6. Take off the heat remove thyme and stir in mixed fish, 1 tsp mustard, lemon, chives and petits pois. Spoon into an ovenproof dish.
  7. Spoon the potato on top and sprinkle with a handful of grated cheddar cheese.
  8. Pop in the oven for 20-25 mins or until golden.