Put a large non-stick frying pan on a low heat. Cook the
onion slowly in the oil and butter until
soft but not brown – this should take about 15 mins.
Add the potatoes to the pan, then cover
and cook for a further 15-20 mins, stirring occasionally to make sure
they fry evenly. When the potatoes are
soft and the onion is shiny, stir in,
followed by the beaten eggs.
Put the lid back on the pan and leave the
tortilla to cook gently. After 20 mins, the
edges and base should be golden, the top set but the middle still a
little wobbly. To turn it over, slide it onto a plate and put another
plate on top, turn the whole thing over and slide it back into the pan
to finish cooking.
Once cooked, transfer to a plate and serve the
tortilla warm or cold. To accompany it you
can take slices of warmed baguette, with a drizzle of olive oil.
