This is a traditional Northern Irish dish of mashed potatoes with milk and sliced green onions. I thought it was a delicious under our St. Patrick's Day Salmon and Leeks recipe. The leeks and green onions really went well together. That said, the green onion flavor is quite strong so I would caution against serving this with anything that might be overpowered by the onion flavor.
Place potatoes into large pot, and fill with enough water to cover. Bring to a boil, and cook until tender, about 20 minutes.
Drain well. Return to very low heat and allow the potatoes to dry out for a few minutes. (It helps if you place a clean dish towel over the potatoes to absorb any remaining moisture.)
Meanwhile, heat the milk and green onions gently in a saucepan, until warm.
Mash the potatoes, salt and butter together until smooth. Stir in the milk and green onion until evenly mixed. Season with freshly ground black pepper. Serve piping hot in bowls. Set out some extra butter for individuals to add to their servings.