One sachet of tuna sandwich filler
One sachet of instant potato
Boil the required amount of water, make the potato, add the tuna to the potato, stir, and eat! Did I mention this was simple to prepare?
Those with a fry pan and the inclination could make tuna fish cakes with the mix.
The ones I use are John West and they come in a variety of dressings, my favourite is the sun dried tomato one.