5 carrots, cut into 1-inch pieces
3 tablespoons unsalted butter
3 tablespoons packed light brown sugar
1 teaspoon kosher salt
Cook rutabagas and carrots in boiling salted water to cover by 1 inch in a large pot until tender, about 30 minutes. Transfer vegetables with a slotted spoon to a food processor and purée with butter, brown sugar, and salt until very smooth. If necessary, transfer purée back to pot and reheat. Purée keeps, covered and chilled, 3 days.
Makes 8 servings.