Grate potatoes.
Preheat the Oven to 450F. Carefully work a spatula under the edges to loosen rosti, then place a plate over pan and using oven mitts carefully turn pan over so rosti ends up on the plate. Drain the potatoes, cool and peel. Cover and keep cold overnight.
This cooling process helps in making wonderful rostis. Using a vegetable peeler, cut the sweet potato into long strips. Peel and dice the onion and garlic. Mix with butter. Add onion and garlic. UPDATES - First Published August 28, 2018.

Wash potatoes thoroughly.

Season with salt and pepper.

REHEATING - Preheat oven to 180C / 350F, place rosti on a baking tray lined with baking paper / silicon mat and pop in oven for 10 minutes or until the rosti is heated all the way through.

Peel the potatoes and boil them for about 10min or until tender. Cook in boiling salted water with cumin for about 20 minutes. Traditional Swiss Rosti (Potato Fritter) ~ Whole 30. Toss the sweet potato strips with the olive oil, garlic, parmesan, and pepper. Pre-heat the oven to 175 C. Form the potato … It would be a good idea to use left over boiled potatoes this way, if you are esp among those who have this habit of refrigerating left over boiled potatoes.

Place in the oven and bake for about 20 minutes until the sweet potato is crisp at the edges and golden brown.

Refrigerate overnight. Place small mounds of the sweet potato onto a baking sheet lined in parchment paper.