01 - Place grated raw potatoes in a clean kitchen towel and squeeze out excess moisture thoroughly.
02 - Mix grated raw potatoes and mashed cooked potatoes in a large bowl until well combined.
03 - Stir in flour, baking powder, salt, and black pepper. Mix until evenly distributed.
04 - Gradually whisk in milk to create a thick, slightly lumpy batter.
05 - Melt 1 tablespoon butter with 1 tablespoon oil in a large nonstick skillet over medium heat.
06 - Drop large spoonfuls of batter into pan, flatten gently to approximately 1/2-inch thickness.
07 - Fry for 3-4 minutes per side until golden brown and crisp. Add remaining butter and oil as needed for subsequent batches.
08 - Transfer cooked pancakes to paper towels briefly to drain.
09 - Serve hot topped with sour cream and sprinkle with fresh chives if desired.