- 1 pound parsnips, peeled and cut into 2-inch lengths
- 1 large Idaho potato (about 8 ounces), peeled and sliced 1 ½ inches thick
- 1 bunch scallions, including tender greens, trimmed, cleaned and sliced thin (about 1 cup)
- ½ cup milk
- 4 tablespoons unsalted butter
- 1 teaspoon grated lemon zest
- Freshly ground black pepper
Pour enough cold water over the parsnips and potatoes in a 3 to 4-quart saucepan to cover them by three fingers. Season generously with salt and bring to a boil over high heat. Cook until tender, about 15 minutes. Add the scallions and cook 3 minutes.
Meanwhile, heat the milk and butter in a saucepan over low heat until the butter is melted. Drain the vegetables thoroughly and return them to the empty pot. Mash the vegetables with a potato masher, gradually adding the milk and butter, to a smooth texture. Stir in the lemon zest and season to taste with salt and pepper. Serve immediately.