Peel the potatoes, then cut into bite-sized cubes. Place the cubes in a heat-proof bowl, wrap with cling film and heat in the microwave until soft.
Completely mash the potatoes with the back of a fork.
Finely chop the onion and stir fry in a frying pan greased with a little oil until browned. Add to the bowl in Step 2.
Once the onions have cooled, mix in the olive oil and salt. Whilst keeping an eye on the consistency of the mixture, add the eggs in one at a time (see Helpful Hints).
Pour the mixture into a frying pan greased with oil. Cook the omelette. Once the edges have become firm, use a plate to flip the omelette over.
[How to flip the omelette:] As in this photo, place the plate over the top of the frying pan and......
Flip everything over in one go! (Don't let the omelette fly out!)
Slide the omelette back into the frying pan. If it loses it's shape, just nudge the omelette around in the pan a bit until it regains a its roundness.
This photo shows the round omelette that I made in the frying pan above.
Story Behind this Recipe
This is a variation of a recipe that I learnt whilst I was living in Spain. Normally you would fry the potato, but I heat them in the microwave to reduce calories. I also changed the technique for mashing the potatoes. Even with all the adjustments, these omelettes will come out tasting very good.
In Step 4, see how the mixture looks, then decide whether you need to use a 5th egg. If there is too much potato and not enough egg, then you will get a crumbly omelette, Or, if you add too much egg, the potato will float to the top. I recommend cooking these omelettes until they're half-cooked, i.e. not completely cooked through to the middle.