01 - Place the chopped potatoes in a saucepan, cover with cold water, and add a pinch of salt. Bring to a boil, reduce heat, and simmer until fork-tender (about 12–15 minutes). Drain and mash until smooth. Let cool slightly.
02 - Squeeze excess moisture from the grated potatoes using a clean kitchen towel or cheesecloth.
03 - In a large bowl, combine the mashed and grated potatoes. Add the milk, melted butter, scallions, flour, baking powder, salt, and black pepper. Stir until just combined; do not overmix.
04 - Heat a large nonstick skillet or griddle over medium heat and add a little butter.
05 - Drop heaping spoonfuls of batter (about ¼ cup each) onto the skillet, gently flattening each to about ½ inch thick.
06 - Cook for 3–4 minutes per side, or until golden brown and crisp. Work in batches, adding more butter as needed.
07 - Transfer cooked boxty to a plate lined with paper towels. Serve warm, garnished with extra scallions if desired.