I mean, I know how I make it, but I wondered what variations there were amongst MNetters.
I use a piece of salmon, a piece of hake, four scallops and four giant prawns. Then I add some frozen peas and some fried mushrooms, and put the cheese sauce on top. I make my own cheese sauce, with mustard and various cheeses.
Finally, I put lots of mashed potatoes on the top, sprinkle with grated cheese and cook for about half an hour. If there are any tomatoes in the house, I slice some on the top, too.