Ended up using this very simple recipe - here's the short version:
* Fry plantain slices in oil
* Mash with something heavy
* Fry again until golden
* Sprinkle with salt
* Enjoy as hot as possible
The thick one actually turned out best, when cut into relatively small slices (about 3-4 cm) and mashed to about 1 cm height.
So delicious... Photo credit goes to the boyfriend :)