2 pounds Idaho or russet potatoes
2 tablespoons butter (1/4 stick)
2 tablespoons oil
salt & pepper to taste
1 1/2 cups (packed) shredded mozzarella cheese
3 tablespoons chopped fresh parsley
Cook potatoes in their peels in a large pot of boiling water until soft, about 25 minutes. Drain and refrigerate overnight.
Peel potatoes and grate using a large-hole grater. Melt 1 tablespoon butter with 1 tablespoon oil in a 10” skillet over high heat. When the oil is hot, lower flame slightly. Sprinkle half the potatoes shreds evenly over the bottom of the skillet. Season to taste with salt and pepper. Sprinkle cheese evenly over potatoes. Sprinkle remaining potatoes over cheese and season once again. Press gently with a large spatula to compact layers. Cook until bottom is browned, about 7 minutes.
Remove skillet from heat. Invert a dinner plate over the skillet and using oven mitts, flip skillet and plate over, turning the pancake onto the plate.
Return skillet to flame and heat remaining butter and oil. Slide the pancake back into the pan with the brown side up. Cook 7 minutes longer until brown on the bottom and the cheese is melted.
Serve sliced in wedges, sprinkled with fresh parsley.