Put the eggs in a small pan of cold water. Set over a medium heat and bring to the boil. Once simmering, cook for a further 8 minutes. Drain the eggs and place in a bowl of ice water or run under cold water for 2-3 minutes.
Peel away the shells, roughly chop and put into a bowl.
Add the mayonnaise to the eggs with salt and pepper and stir to combine.
Spread the filling on the sandwich and serve.
Notes
This one is really made in minutes. The only thing that might slow you down is the peeling of the eggs. Top tip is to roll them on your counter top to crack and release the shell from the egg inside.