This is a recipe that can be made in a small portion for 2 people or a large dish full to feed a small army.
From start to finish the dish takes only as long as it takes to cook the noodles. Then put into the oven for 15 - 20 minutes until bubbling and the cheese is melted and browned.
1 x 425 gram can tuna in water,drained and flaked, 2 cups dry pasta, any small pasta will do, 1/4 red onion finely chopped, 2 tsps dijon mustard, 2 tbsps butter, 3 tbsps plain flour, 4 cups milk, salt and pepper to taste, 1/2 cup grated tasty cheese for sauce + 1/4 cup for topping, 1/4 cup dried breadcrumbs
Put oven on 180.c to heat. Bring a large pot of water to the boil and the pasta, cook until tender. When cooked remove from heat, drain and return to the saucepan.
While the pasta is cooking make the bechamel. I make it in a 2 litre pyrex jug in the microwave, this stops the need for constant stirring and the possibility of burning the sauce.
Melt the butter 30 seconds on high, add the onion, cook on high for 1 minute. Stir the onion should have softened if it was diced finely, if still very hard cook another minute. Add the flour, the mixture will be quite thick, cook for 1 minute on high. Add the milk, mustard, salt and pepper. Whisk together don't worry if the flour mix is in lumps it all comes together. Cook on high for 2 minutes, whisk. You may need to scrap the sides of bottom of the jug if the flour mix is stuck to it. Cook for another 2 1/2 - 3 minutes on high. Whisk, now you want a smooth sauce that isn't to thick (think thick cream) because when you add the tuna, cheese and noodles they will thicken the sauce.
When the sauce is the right consistency, taste you made need more salt, pepper or mustard. Add the cheese, stir until melted. The add the tuna stir gently. Now I generally pour this over the pasta that has been returned to its cooking saucepan, stir together gently. Spoon into a baking dish large enough to hold it. Top with breadcrumbs then cheese. Bakes 15 - 20 minutes until bubbling around the edge and the cheese has melted and browned.
Now you can make this ahead of time, it will need longer to cook 20 - 30 minutes.