Depending on the seller, these will be called either Rose Virginia or Rose Jersey but I can't find any information about them under either name or even variations of the name. I have been told that these are excellent in gratins.
This means that the dish I've cooked is that often incorrectly made Jansson's Temptation (Jansson's Frestelse). It is layered dish of potatoes, onions and pickled sprats and it is this last ingredient that usually causes the problems.
The translation of the Swedish word for sprats sounds awfully like anchovy which means that people end up adding anchovies. Having now tasted sprats it couldn't be a more different flavour. The sprats are pickled in a sweet brine giving them a slightly sweet flavour - the sprat itself is soft, certainly not dense and salty like an anchovy.
In case you're wondering, this is what the pickled sprats look like.
After completing the layering process of potato, cooked onion and pickled sprats it is covered with cream and baked until golden and soft throughout. In this version I've replaced some of the cream with milk.
4 potatoes, peeled and sliced very finely
2 onions, sliced finely
1 tin pickled sprats, drained, roughly diced
sea salt and white pepper
Cook the onions:
Heat a little oil and a knob of butter in a pan over a low heat - when the butter is sizzling add in the onions and cook very slowly until golden and soft - about 15 to 20 minutes.
Assemble the dish:
Generously butter an oven proof dish.
Cover the base in a layer of potatoes - top this with some of the onions and a scattering of pickled sprats. Season with a little sea salt and white pepper. Continue layering until all the mixture is used, finishing with a layer of potato. I generally only season every 3rd layer.
The final step is to cover the dish in a mixture of cream and milk - I use a 60:40 cream to milk ratio - then season with a little more sea salt and white pepper. Some recipes will also suggest sprinkling over with parmesan - it's up to you, personally I don't think it needs it.
Bake in a preheated 160°C oven until golden and cooked through - depending on the size of the dish and its thickness, this could take an hour or more.
It's not for everyday but will sit nicely as a special occasion dish.