2 rutabagas (about 2½ pounds), peeled and cut into 1-inch pieces
5 carrots, cut into 1-inch pieces
3 tablespoons unsalted butter
3 tablespoons packed light brown sugar
1 teaspoon kosher salt
1. Cook rutabagas and carrots in boiling salt water to cover by 1 inch in a large pot until tender, about 30 minutes.
2. Transfer vegetables with a slotted spoon to a food processor and puree with butter, brown sugar, and salt until very smooth. If necessary, transfer puree back to pot and reheat.