This is a take on champ, a traditional Irish dish of potatoes mashed with scallions or spring onions. I use buttermilk and Yukon Gold potatoes to give the potatoes a lot of flavor without tons of butter. To mash the spuds, I strongly recommend a food mill. The mill yields fluffy, lump-free potatoes, and even better, it will separate most of the skins from the potatoes, so you don’t need to peel them! —Savorykitchen
Wash the potatoes, peel them if desired, and cut into large chunks. Place them into a pot of well-salted cold water (enough water to cover by 1”) and bring to a simmer. Simmer until potatoes are tender, about 15-20 minutes.
Slice the scallions (the green and white) into thin rings. While the potatoes are cooking, in a small skillet, melt 2 ounces of butter. When melted, add the scallions to the skillet and stir until they have wilted and are a little softened. Set aside and keep warm.
Drain the potatoes and mash using a food mill, potato ricer, hand blender or your chosen implement of destruction. I like smooth, silky mashed potatoes, but if you like ‘em lumpy, I won’t judge.
Add the remaining 2 ounces of butter to the potatoes and stir in. Add buttermilk until the potatoes are light and not too thick. Again, this is partly a personal choice. For me, 1 cup of buttermilk is the maximum needed to get the right blend of richness and lightness. Taste for salt and pepper and adjust as needed.
Stir about half of the scallion mixture into the potatoes. Turn the potatoes into a warmed serving dish and top with the remaining scallions.