2 1/2 pounds (5-6 large) Yukon Gold potatoes , scrubbed and sliced 1/8 inch thick (see note)
5 tablespoons unsalted butter , melted
1 tablespoon cornstarch
1 teaspoon table salt
1/2 teaspoon ground black pepper
1 1/2 teaspoons chopped fresh rosemary leaves (optional)
1. Adjust oven rack to lowest position and heat oven to 450 degrees. Place potatoes in large bowl and fill with cold water. Using hands, swirl to remove excess starch, then drain in colander. Spread potatoes onto kitchen towels and thoroughly dry.
2. Whisk 4 tablespoons butter, cornstarch, salt, pepper, and rosemary (if using) together in large bowl. Add dried potatoes and toss until thoroughly coated. Place remaining tablespoon butter in heavy bottomed 10-inch ovenproof nonstick skillet and swirl to coat. Place 1 potato slice in center of skillet then overlap slices in circle around center slice, -followed by outer circle of overlapping slices. Gently place remaining sliced potatoes on top of first layer, arranging so they form even thickness.
3. Place skillet over medium-high heat and cook until sizzling and potatoes around edge of skillet start to turn translucent, about 5 minutes. Spray 12-inch square of foil with nonstick cooking spray. Place foil, sprayed side down, on top of potatoes. Place 9-inch cake pan on top of foil and fill with 2 cups pie weights. Firmly press down on cake pan to compress potatoes. Transfer skillet to oven and bake 20 minutes.
4. Remove cake pan and foil from skillet. Continue to cook until potatoes are tender when paring knife is inserted in center, 20 to 25 minutes. Return skillet to medium heat on stovetop and cook, gently shaking pan (use potholder—handle will be hot), until galette releases from sides of pan, 2 to 3 minutes.
5. Off heat, place cutting board over skillet. With hands protected by oven mitts or potholders, using 1 hand to hold cutting board in place and 1 hand on skillet handle, carefully invert skillet and cutting board together. Lift skillet off galette. Using serrated knife, gently cut into wedges and serve immediately.
WHY THIS RECIPE WORKS:
Pommes Anna, the classic French potato cake (or galette) in which thinly sliced potatoes are tossed with clarified butter, tightly shingled in a skillet, and cooked slowly on the stovetop, delivers showstopping results, but it requires so much labor and time that we’re willing to make it only once a year. We wanted a potato galette with a crisp, deeply bronzed crust encasing a creamy center that tasted of earthy potatoes and sweet butter—and we wanted one we could make on a weeknight. We started by neatly arranging just the first layer of potatoes in the skillet, and casually packed the rest of the potatoes into the pan; once the galette was inverted onto the plate, only the tidy layer was visible. We swapped the traditional cast-iron skillet for a nonstick pan and achieved superior browning by starting the galette on the stovetop, then transferring it to the bottom rack of the oven. Regular melted butter was just as good as clarified and less work, and for a galette that held together but wasn’t gluey, we rinsed the potatoes to rid them of excess starch, then incorporated a little cornstarch for just the right amount of adhesion. And in lieu of occasionally tamping down on the galette during cooking as in traditional recipes, we simply filled a cake pan with pie weights and set it on the galette for a portion of the baking time.