Grate the potatoes. In a clean cloth, wrap half of the grated potatoes at a time and wring over a sink to drain, leaving about 6 cups of grated potatoes.
In a bowl, combine the grated potatoes, 1 tbsp of the butter and the salt. Season with pepper.
In a 9-inch (23 cm) non-stick skillet over medium-high heat, pour 2 tbsp (30 ml) of the butter. Spread and lightly press the potatoes on the bottom and sides of the skillet. Cover and cook for 6 to 8 minutes or until the potato edges begin to brown.
Off the heat, cover the skillet with a plate and flip to turn the rösti out onto the plate. Heat the remaining butter. Slide the rösti back into the skillet and continue cooking over medium heat for about 10 minutes or until the potatoes are tender.
Slide the rösti out onto a plate. Cut into wedges and serve.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.