Tuna casserole

Ingredients

• 12 1/4 ozpasta shells, or macaroni
• 2 ozunsalted butter
• 1onion, finely chopped
• 7 ozchestnut mushrooms, sliced
• 1 3/4 ozall-purpose flour
• 3 cupswhole milk, warmed
• 2 tspDijon mustard
• 14 ozcanned tuna, drained, in spring water
• 7 ozfrozen peas
• 5 1/4 ozCheddar cheese, grated
• 2 tspsea salt
• 1 tspblack pepper
• 1 3/4 ozdried breadcrumbs, for the topping
• 1/4 ozfresh parsley, chopped

Method

1. 1

   Boil the pasta in well-salted water for two minutes less than the packet says, so it still has a real bite, then drain it.

2. 2

   Melt the butter in a large pan and cook the onion and mushrooms until the mushrooms have released their water and it has boiled away again.

3. 3

   Stir the flour in and cook it out for a minute, then add the warmed milk gradually, whisking after each addition, until you have a smooth sauce thick enough to coat a spoon. Stir in the Dijon, the salt and the pepper.

4. 4

   Take the pan off the heat and fold in the drained pasta, the tuna in large flakes, the frozen peas and two thirds of the Cheddar. Tip it into a baking dish.

5. 5

   Heat the oven to 400°F. Mix the breadcrumbs with the remaining Cheddar, scatter it over the top, and bake until the crust is golden and the sauce is bubbling at the edges.

6. 6

   Let it stand for five minutes so the sauce settles, then scatter with parsley and serve.