Erythronium couldn't tell you which one though

It looks a bit like E. dens canis maybe 'Old Aberdeen' Have a look at one on this website.
https://www.avonbulbs.co.uk/autumn-planted-bulbs/erythronium

Possibly Scotsgran, depends if the leaves go with the flower.

The link shows the leaves and a close up of the flower. Without actually comparing them when looking at them it has to be the owners choice.

Yes, Erythronium dens-cansis. I didn't know that they had started trying to put varietal names to these now but, from the photo, this may be growing wild. They are native to southern Europe including the Iberian penninsula.

So highly unlikely to be a varietal...

Thank you Mg and Bb. How lovely to see them growing in the wild. I missed that this query came from Spain and also how many plants were growing in what looks like a wild setting.