01 - Place peeled potatoes in a large pot and cover with cold, salted water. Bring to a boil and simmer for 12–15 minutes until fork-tender. Drain thoroughly.
02 - Mash potatoes until smooth. Stir in butter and milk while still hot. Let cool for 5 minutes.
03 - Add sliced scallions, flour, salt, and pepper to cooled mash. Mix until soft, slightly sticky dough forms; do not overmix.
04 - Lightly flour work surface. Turn out dough and gently knead until just combined. Pat or roll to ½ inch thickness. Cut into rounds using a 3 inch cutter or shape by hand.
05 - Heat large non-stick skillet over medium heat and melt butter. Cook potato cakes in batches for 3–4 minutes per side until golden and crisp. Add more butter as needed.
06 - Serve hot, garnished with extra scallions or sour cream if desired.