2 pounds swede (rutabaga), peeled and cubed
¼ cup butter, softened
1 teaspoon mustard powder
1 bunch scallions, finely chopped
salt and ground black pepper to taste
Place potatoes and swede in a large pot; cover with water. Bring to a boil. Cook until tender, about 15 minutes. Drain. Add butter and mustard powder; mash until well incorporated. Stir scallions, salt, and pepper into the mash.