The day before, cook the potatoes, with skin, in a pot of salted boiling water for 10 minutes or until tender (but not falling apart).

Let the potatoes cool and chill them overnight.

The next day, peel and coarsely grate the potatoes. Season with salt, pepper and the fresh thyme.

In a different bowl, combine the cheese and stir well. Reserve.

Heat 1 tablespoon of butter and 2 tablespoons of olive oil in a medium sized sauté pan, over medium heat.

Add half of the grated potato, spreading it out evenly to cover the bottom of the pan.

Allow to cook for about 4 minutes, or until the sides start to turn golden, while shaping it into a flat cake, pressing down lightly.

Pour all the cheese filling into the potato pancake, leaving a small edge all around.

Then, spread out the remaining potato on top of the cheese, pressing it down and around as you go, covering all the cheese.

Continue to cook for 5 more minutes. When the edges of the bottom potato cake are golden, gently shake the pan to loosen the Rösti. Then, flip it with the aid of a plate that is larger than the sauté pan.

Add 1 tablespoon of butter and some olive oil and, when hot, slide the Rösti back into the pan, uncooked side down.

Let it cook for 5 to 7 more minutes or until the bottom is golden brown, adding more olive oil if necessary.

Remove to a plate covered with paper towel to soak the excess grease.

Let it stand for 5 minutes before serving!