01 - Place the grated raw potatoes in a clean kitchen towel and squeeze out as much liquid as possible. This step is crucial for achieving crispy pancakes.
02 - In a large bowl, combine the grated potatoes, mashed potatoes, and scallions. Mix thoroughly to distribute ingredients evenly.
03 - In a separate bowl, whisk together the flour, baking powder, salt, and pepper until well combined.
04 - Add the dry ingredients to the potato mixture and mix gently until just incorporated. Avoid overmixing to prevent tough pancakes.
05 - In another bowl, whisk the milk, egg, and melted butter until smooth. Pour this into the potato mixture and stir until just combined.
06 - Heat a large skillet or griddle over medium heat. Add a thin layer of butter and allow it to melt and coat the surface evenly.
07 - Drop heaping spoonfuls of the batter onto the skillet. Use the back of the spoon to flatten each to about 1/2 inch thickness for even cooking.
08 - Cook for 3-4 minutes per side until golden brown and crisp. Work in batches as needed, adding more butter to the skillet between batches.
09 - Transfer cooked pancakes to a paper towel-lined plate to drain excess butter. Serve hot, garnished with sour cream and chives if desired.