Purple potatoes

I've just come back from a few days skiing in Switzerland and am on a quest to seek out purple potatoes!

The potatoes in question are Vitelottes potatoes - I had them with a rump-steak while out for dinner at the Bella Tola hotel in St. Luc- they looked bizarre but tasted delicious.

Apparently they are naturally violet/blackish when plucked from the soil and manage to retain their colour when they're cooked. My dad has grown some purple Royal Burgundy beans but they lose their colour when you boil them so aren't nearly as impressive.

These potatoes had a really earthy flavour and were crushed with nuts to bring out the flavour- I'm sure they must be available over here so I'll be scouring the supermarket aisles and market stalls to find them!