Preheat oven to 350 degrees. Place parsnips in a medium saucepan. Add enough water to cover by 1 inch, and 1 teaspoon salt. Bring to a boil. Reduce to a simmer, and cook until tender, about 6 minutes; drain.
Generously butter a 9-by-13-inch baking pan. Arrange parsnips in pan and sprinkle with sugar. Dot with butter, and season with salt and pepper. Bake until parsnips are tender and glazed with sugar and butter, about 20 minutes.