My ideal rosti potato is crisp on the outside and soft in the middle. And for this I use the mandolin to cut spaghetti like strands. If you use a grater, by the time the rosti is cooked, the potato has disintegrated to mash, so you may as well have used mash potato in the first place. If using a mandolin whatever you do use the guard - it saves a trip to the local casualty department. Half a baking potato just does one portion – so it’s an idea to have a another one as spare. Salt it quite well, then leave it to macerate for 10 - 20 minutes. The salt brings out the water.
Then squeeze the potato in a tea towel, a little bit at a time so it is really dry (without the water content they go crispy). Mix in corn flour and a beaten egg (I probably use about one whole egg for 6 - 8 rosti, and maybe 2 tbsp corn flour, but I never measure) and black pepper. The egg and cornflour bind it together so it doesn’t fall apart. If you have egg white left over in your fridge after using just the yolks, use this for your rosti - it's an ideal opportunity for using left overs.
Then you fry them like my crispy noodles - there are some good tips there on frying them.
When cooked on both sides place rostis on a baking tray, then they just need about 5 - 10 minutes in the oven to finish cooking the middle. Then you can chill them if doing them in advance. They need just 5 - 10 minutes in the oven to re-heat when you are ready.
- How to make a stainless steel pan non-stick
- If you make very thin, crisp ones, they don’t need extra cooking in the middle.
- If you leave the raw potato salting for more than 20 minutes it will start discolouring badly.
- A lot depends on the type of potato you use. Desiree, King Edwards, Estima are all very good.
- You can make a large one - the size of the whole frying pan and cut it into pieces.
- They also freeze very well - so you could do them in advance. Just put them flat on a tray in the oven frozen like you do roast potatoes.