Tuna Spinach Mornay with Mash

Nothing fancy here, but this is a recipe my daughter loves

50g butter
1 med onion (thinly sliced)
1/4 cup plain flour
500ml milk
frozen spinach
frozen peas
425g can of tuna
can corn kernals

Boil potatoes and mash when soft with some milk and butter.

Heat the spinach and peas and drain along with the tuna and corn.

Melt butter and add onions. Stir until soft, then add the flour and cook until mixture thickens. gradually add the milk, stirring until mixture boils and thickens. Remove from heat and stir in the other ingrediants.

Pour into a casserole dish. Top with mashed potatoes and grated cheese. Bake in the oven until the cheese has melted.