Literally translated, paillasson means “doormat.” Raw potatoes are shredded, pressed into a nonstick pan, and cooked to create a compact cake that is excellent with any kind of roast or on its own with a salad. The dish, also called pommes Darphin, after the chef who created it, is similar to what the Swiss call rösti potatoes.
If you are reluctant to attempt flipping the compacted potato cake over in the skillet with a spatula, loosen it (it should be a solid mass) around the edges and underneath, cover the pan with a flat lid or plate and, holding the lid in place, invert the pan. Then slide the potato cake, crusty side up, back into the skillet to cook on the other side.
3 baking (Idaho) potatoes (about 8 ounces each)
2 tablespoons corn oil
1 tablespoon unsalted butter
4 scallions, trimmed (leaving some green) and minced (1/2 cup)
1/2 teaspoon salt
1/4 teaspoon freshly ground black pepper
Peel the potatoes and, using the large holes of a box grater, shred them. (You should have about 4 cups.) Squeeze the potatoes gently with your hands to remove some of the liquid.
Heat the oil and butter in a 10-to-12-inch nonstick skillet until hot. Add the potatoes, scallions, salt, and pepper and sauté, stirring occasionally, for about 2 minutes, until the potatoes are well mixed with the seasonings. Press on the mixture with the back of a spoon to compact it, cover, reduce the heat, and cook gently for about 12 minutes.
Flip the potato mixture over and cook it for 10 minutes on the other side.
Invert it onto a serving plate, cut into wedges, and serve.