Combine fish pie with mac 'n' cheese to make this crowd-pleasing dinner. The dish freezes well, so you can make ahead if you like for busy weeknights. This recipe is best suited to serve 6, however if scaling this recipe up or down, make sure to change the size of the baking dish accordingly.
Based on 6 servings, adjust as needed.
Add the butter to a medium size saucepan and allow it to melt over a low heat. Add the flour and mix to a paste. Gradually add the milk while whisking, allowing the mixture to boil. and thicken until you have a smooth white sauce. Remove from the heat, add the mustard, most of the cheese (save a handful for the top), peas and parsley.
Meanwhile, boil the pasta in a large pan of water following pack instructions until just cooked. Drain.
Heat the oven to 200C/180C fan/gas 6. Tip the pasta into the sauce and add half the fish, stir everything together then tip into a large baking dish. Top with the rest of the fish, pushing it into the pasta a little, then scatter with the remaining cheese. Bake for 30 mins until golden, then serve with salad, if you like.