The following is a recipe for the staple Spanish bar snack tortilla1 (aka 'Spanish tortilla'). It was taught to this Researcher during his time as a student in Zaragoza, Spain by his neighbour, Milagros. Milagro means 'miracle' in English and this recipe is just that - it creates a mouth-watering substantial snack from the simplest of ingredients.
In a large (12-inch diameter, 2-inch deep) frying pan sweat the onions in about three good glugs of oil. When frying the onions, make sure they don't brown - you know when this stage is done when the onions are slightly transparent and soft.
Now add the potatoes and more lashings of oil, and mix. You'll need to make sure that the potatoes have a covering of oil and there remains about 1cm of oil to fry the contents of the pan in.
This is when you need to salt the potato/onion mix. You need to be a little generous with the salt as it really brings out the flavour of the onions and potatoes. However, don't be heavy-handed - you can always add more later.
Fry the mixture, turning every now and then, until the potatoes are soft and slightly browned. Don't over-fry them. Meanwhile beat your eggs in a large mixing bowl.
When the potatoes are cooked, let them cool for a minute or two and then add them to the eggs. After you have mixed the two together, transfer back to the pan and cook on a medium heat.
You'll need to turn the tortilla over at some stage. This is best done when you see the mixture on top bubbling away and slightly cooking the egg. At this point, put a plate on top of the pan and, over a sink, turn the half-cooked tortilla onto it. Remove the pan and replace on the heat and gently scrape the tortilla - cooked side up - back into the pan.
Cook for a further 3-5 minutes, turn onto a clean plate and serve.
Don't worry if the tortilla is slightly runny, this is normal. If you are worried about food poisoning, just cook the tortilla a little longer.
Variations and Cheating Tips
If you're not brave enough to flip the tortilla as mentioned above, you can place the tortilla under the grill, browning it that way.
If you want to add a little pizazz, you can add any one of the following: mushrooms, bacon, peppers, or any other vegetable or meat that grabs your fancy.