Now the good señoras of Spain would blanch at the method I am about to describe. The traditional method is to slice raw potato into small thin slivers and fry them gently in a lot of olive oil until they are softly cooked. But I haven't the patience and my method is just as tasty and lower in fat and faff. I do agree with the Spanish, however, that the only acceptable addition to a tortilla is onion. If you must use peppers or mushrooms or some other godawful ingredient, call it a frittata, your recipe is not welcome in the land of the tortilla.
Incidentally, the word "Tortillera" in Spanish means omelette seller, but it also means lesbian, somewhere in the region of "Dyke". But the Spanish lesbians have not reclaimed this vocabulary for their own in the way that our gays and lesbians are proud to be dykes and queers. So if you have call to call a Spanish lady a "Tortillera",make sure she's selling omelettes.
Just as pancakes are all about the pan, so it is true for omelettes. You need a 7 or 8 inch non stick pan for this, and I recommend the Tefal Jamie Oliver pans you can get from Bentalls, which survive my dishwasher admirably.
These ingredients can be increased proportionally depending on the size of your pan - but don't use a pan greater than 10 inches unless you have Iberian genes from both sides of the family - it's just too hard to handle.
5 Large Fresh Eggs, beaten with Salt and Pepper
Potatoes (e.g. Desirée or Maris Piper) (300g)
A large white onion, sliced finely.
Plenty of olive oil (extra virgin but not your best grassy green)
Peel and boil your potatoes (chopped into evenly sized chunks) until they are not quite done - you need them to retain their shape. Drain them in a colander and allow them to cool to the point that you can handle them comfortably. They will also dry out a little at this time and this will enable them to absorb more oil and flavour.
Meanwhile, gently fry your onions in your omelette pan with olive oil and a little salt, until softened but not browned. Switch off the heat.
Slice your potatoes as thinly as you dare and fry them on a gentle heat mixed with the onions, adding oil as necessary and turning them periodially until most of the potatoes have delicious chewy brown bits.
Turn the heat down to its lowest level and add your eggs. If your pan doesn't look full enough quickly beat up another egg and add it to the pan.
The omelette should begin to solidify at the edges and here the magic begins, with a wooden or non-stick spatula start lifting up the edges of the omelette and tilting the pan so that the uncooked egg can run underneath the cooked omelette. It's OK if the omelette breaks slightly as you do this, it will all come together at the end.
When you have only the thinnest layer of uncooked egg on top, try to loosen the omelette at the edges with your spatula. Take a clean dinner plate and place it face down on top of your pan, then invert the lot so that the omelette is now on the plate. It helps to do this over a clean draining board if you're not feeling confident. Now is the time to check your frying pan and scrape off any bits that have stuck (you either needed more oil or you need a new pan), add a bit more olive oil if necessary and slide the omelette from the plate back into the pan,so that the uncooked side is now on the bottom. Another few minutes and your omelette will be done - if in doubt poke it in the middle with a knife to check that it is cooked through.
The flavour of the omelette will improve if you let it cool a little before serving with crusty bread and a salad. If you have any left over this is a good lunchbox meal, although the potatoes will discolour after a day.