My fave was tuna and beans on toast.
It sounds pretty rank (ok it smells rank too) but has everything you could need.
Ingredients
1 tin heinz beans
1 tin tuna, drained
Chuck it all in pan and heat up, to lava like consistency / temperature.
Toast the bread while its cooking..
Chuck the muck on top – job done!
You can liven it up with any of your faves from the spice rack / sauce selection (salad cream seemed to work well) or cheese.