Spanish Potato Omelette - Tortilla de Patatas (スペイン風ポテトオムレツ）

When I was small, I did not like to go to church on Sundays except for one thing.
That is this Tortilla de Patatas sold in the melinda in the church.
Even though it was in Japan, some of sisters of the church are from Spain, and they made unforgettable Tortilla.
Now I can make it by myself, and it turns out to be pretty good !
The key to make tasty tortillas is to use a lot of olive oil without any hesitation.
Potato needs to be boiled in oil which is almost like frying potatoes to get that sweet flavor.