Peel the potatoes and cut them in ~1cm cubes
Peel and finely slice the onion. Drizzle 2 tbs olive oil into a small frying pan over medium heat, then add the onion, cover and cook for 30 min, or until the onion are turning golden.
Pour 3 tbsp of olive oil in a big, tall, nonstick frying pan (better with vertical sides as it will be quite tall).
Throw in the potatoes and add the salt.
Fry the potato on medium-low heat, until the potatoes are tender and slightly golden brown (lower fire if they start getting more brown, the most important is the tenderness).
Whisk the chickpea flour with water in a big bowl.
Add the fried potatoes, courgette and onion to the chickpea mix in the big bowl and mix it well. Now it's the last chance to nail the salt levels so I recommend you to taste it and add more salt if needed. You can even add a touch of black pepper, if you want ;)
Clean the frying pan from the remnants of onion/potatoes with kitchen paper (it will get burnt if not done). Pour the remaining oil in it and wait for it to get warm. If your frying pan is nonstick you can reduce the amount of oil, but it will help on cooking the borders of the omelette better and faster (which is crucial to flip it without problems!).The ideal temperature of the oil is when splashing a drop off the mix it gets cooked almost instantly.
Pour the mixture to the frying pan, levelling it well. If the oil was at the right temperature the borders will start to cook right away.
Cook for 4 minutes and after transfer to preheat oven for about 25 min.
To see if the omelette is cooked, take a toothpick and insert it in the middle, down to the bottom. Then take it back slowly. If the toothpick is dry, the omelette is cooked. If not, cook for another 5 min in oven.
After it's cooked, you can serve the omelette in round plate around the same size and remove the excess of oil from it with kitchen paper. I recommend it to be served at room temperature rather than hot, and for an even better touch leave it in the fridge for some hours and take it out 30 min before serving... I'm always told that it tastes even better the next day!
