1) In a medium saucepan or small pot, cover potatoes with cold water.
Season generously with salt and bring to a simmer. Continue to
cook at a simmer until you can just pierce the potatoes with a paring
knife, about 25 minutes; make sure not to cook them so long their skins
split. Drain potatoes, allow them to cool to room temperature, and
then cover and refrigerate at least 8 hours, preferably overnight.
2) When ready to cook, peel the potatoes and grate into a mixing bowl.
Season with salt, nutmeg, onion and garlic powder to taste.
3) Grate the cheese into the mixing bowl. Dice the bacon and add to the
bowl as well. Mix well without mashing the potatoes.
4) Melt one tablespoon of butter over medium-high heat. Once foaming,
add potatoes, and form an even disc, about 1 inch thick.
Cook until deep golden brown and crisp on the bottom, about 12-15
minutes; lower heat if needed to prevent scorching.
5) Using a large plate, flip the rösti to invert it, adding the
remaining butter to the bottom of the pan.
Cook until deep golden brown and crisp on the second side, about 10
minutes longer; adjust heat as necessary to promote even browning but
prevent scorching.
Notes
1) Add a drizzle of olive oil to the butter to prevent it from burning.
2) Substitute cured cheddar for gruyere.
3) Switch up ingredients for further variations, ie. add onion instead
of bacon.
4) Parboiling and cooling the potatoes is crucial and the most important
step in making rösti.