Dice potatoes and onions.

Steam potatoes until al dente.

Fry onions until translucent.

Whisk egg with salt and pepper.

Mix everything together.

Pour into a pan with plenty of olive oil.

Fry on both sides (flip with the help of a large plate once the egg has set enough).

It should still be slightly runny in the middle.

Infinitely variable with different vegetables or bacon, for example.