These onions are braised withbutter and sugar.
Peel the onions, and trim roots, leaving enough to keep onion intact. Cut them lengthwise in halves or quarters, depending on their size.
Place in a large skillet with butter, sugar, salt, pepper, and enough water to come halfway up sides of onions. Bring to a boil over medium-high heat, reduce to medium-low, and cook, covered, until the onions are tender, about 20 minutes. Uncover, raise the heat to medium, and cook, stirring occasionally until caramelized, 30 to 40 minutes.