1. Heat oven to 180C/fan 160C/gas 4. Boil the pasta for 2 mins less time than stated on the pack. To make the sauce, melt the butter in a saucepan and stir in the flour. Cook for 1 min, then gradually stir in the milk to make a thick white sauce. Remove from the heat and stir in all but a handful of cheese.

2. Drain the pasta, mix with the white sauce, tuna, sweetcorn, parsley, and peas then season. Transfer to a baking dish and top with the rest of the grated cheese. Bake for 15-20 mins until the cheese on top is golden and starting to brown.