Grate potatoes in a food processor and then remove to a bowl. Add the salt and let sit for 5 min., potatoes will brown slightly but don't worry they are still fine.

Heat a large cast iron pan (10") with the canola oil on medium high heat. Working quickly squeeze the water well from the potatoes in handfuls and add in mounds to the pan. Reduce heat as needed.

Flatten out the potatoes into one large rosti. Alternatively you can do small ones which are easier to handle. Continue cooking and pressing down on the rosti with the spatula. Adjusting the heat again as needed. Don't let them brown too quickly.

When browned turn the potatoes in one motion to cook the other side. When browned on both sides slide out onto a plate and blot with a paper towel to remove excess oil. Serve immediately with a garnish of parsley.