- 2 pounds russet potatoes, peeled and cubed
- 2 pounds swede (rutabaga), peeled and cubed
- 1/4 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.