CRISPY POTATO, ONION, AND MUSHROOM CAKE (AKA RÖSTI) SERVES 2 OR 3 3 medium russet (baking) potatoes (about 1 pound), rinsed and cut into 1⁄16-inch matchsticks or grated on the large holes of a box grater 5 tablespoons olive oil 1 medium onion, finely sliced (about 1 cup) 4 ounces button mushrooms, finely sliced 2 medium garlic cloves, minced or grated on a Microplane (about 2 teaspoons) 1 teaspoon fresh thyme leaves Kosher salt and freshly ground black pepper Spread the potatoes on a large microwave-safe plate and microwave on high until hot all the way through and softened but still slightly crunchy, about 5 minutes Meanwhile, heat 1 tablespoon of the oil in a 10-inch castiron or heavy-bottomed nonstick skillet over mediumhigh heat until shimmering Add the onions and mushrooms and cook, stirring and tossing occasionally, until softened and starting to brown, about minutes Add the garlic and thyme and cook, stirring frequently, until fragrant, about 30 seconds Season to taste with salt and pepper Transfer to a small bowl and wipe out the skillet Heat tablespoons oil in the skillet over medium heat until shimmering Add half of the potatoes and press into the bottom of the pan with a rubber spatula Season with salt and pepper Spread the onion/mushroom mixture evenly over the potatoes and top with the remaining potatoes Press down into an even disk, using the spatula Season with salt and pepper Cook, swirling and shaking the pan occasionally, until the potatoes are deep golden brown and crisp on the first side, about minutes Carefully slide the rösti onto a large plate Set another plate on top of it, upside down, grip the edges, and invert the whole thing so the rösti is now cooked side up Heat the remaining tablespoons oil in the skillet and slide the rösti back in Season with salt and pepper Continue cooking, swirling and shaking the pan occasionally, until the rösti is deep golden brown and crisp on the second side, about minutes longer Slide the rösti into a cutting board Serve immediately, with aioli or mayonnaise, or ketchup ... and crisp on the first side, about minutes Carefully slide the rösti onto a large plate Set another plate on top of it, upside down, grip the edges, and invert the whole thing so the rösti is now cooked side up... the whole thing so the rösti is now cooked side up Heat the remaining tablespoons oil in the skillet and slide the rösti back in Season with salt and pepper Continue cooking, swirling and shaking the pan occasionally, until the rösti is... tablespoons oil in the skillet over medium heat until shimmering Add half of the potatoes and press into the bottom of the pan with a rubber spatula Season with salt and pepper Spread the onion/mushroom