In a large pot of boiling water, blanch the onions for 2 minutes. Drain and transfer to a bowl of ice water to cool. Gently squeeze the onions from the root end until they pop out of their skins; discard the skins.
In a skillet big enough to hold the onions in a single layer, combine the onions, wine, jelly, butter, rosemary, 1/2 tsp. salt and 1/8 tsp. pepper. Bring to a boil over medium heat and cook, stirring occasionally, until the liquid is reduced to a glaze and the onions are tender and coated, about 25 minutes.