Sweet-potato pancakes seasoned with rosemary are the perfect side dish for any wedding reception menu.
Preheat oven to 400 degrees. Peel russet potato and grate on the large holes of a grater (about 1 1/2 cups); soak in cold water for 10 minutes. Meanwhile, peel and grate sweet potato (about 1 cup). Strain grated russet potato; squeeze dry. Combine potatoes in a medium bowl; stir in flour, rosemary, salt, and pepper.
Heat 1 tablespoon oil in a medium nonstick oven-safe skillet over medium heat. Shape half the potato mixture into a 5-inch patty; place it in the pan, patting it back together as necessary. Cook over medium heat until a golden-brown crust forms, 5 to 7 minutes, gently shaking the pan occasionally to make sure cake does not stick to the bottom. Use a spatula to gently turn over the cake; add another 1 tablespoon oil to the pan. Immediately transfer pan to the oven. Bake until cooked through, 12 to 15 minutes. Repeat process for remaining potato pancake.
Cut pancakes into 1 1/2-inch wedges, top with Parmesan shavings, and serve warm.