The trick to cooking a Spanish tortilla is in the method of cooking. It is a very different method from cooking an omelette. You will also need a good non-stick frying pan.

Spinach (as much as you want as it disappears when wilted)
2 Garlic cloves, finely chopped
1 large onion, diced
6 eggs
Salt to taste
Olive oil to fry with

Place enough olive oil in the frying pan, just to cover the bottom.
Heat it
Add the onions and cook until soft.
Add the garlic and fry on a low heat until just beginning to brown.
Add the spinach and wilt down. If you use a lot of spinach, add a little at a time to ensure it all wilts down.
Add salt to taste.

Tip the onion and spinach into a collander to allow the water to drain off.
In a jug, crack the 6 eggs and beat.
Put the onions and spinach into a large bowl and pour on the eggs. Mix well.

Add a little more oil to the frying pan and then pour in the mixture. Cook on a medium heat until the top starts to solidify.
Take off the heat and place a plate over the tortilla.

Turn the pan over...the tortilla should now be on the plate. Add a little more oil to the pan and then slide the tortilla off of the plate back into the pan.
Cook for a further 5 minutes or until beginning to brown.
Turn out onto a plate as before and serve.

We eat this with a lovely fresh salad and bread.