Trim and peel onions; halve crosswise and place in 1 1/2 to 2-quart round baking dish. Add 1 inch of water, cover dish with lid or transparent wrap and cook at high power for 20 minutes, rotating dish once, or until fork-tender. Meanwhile, combine apple jelly, mustard, ginger root, vinegar and cornstarch in saucepan, stirring with wire whip until blended. Stir in apple cider and cook, stirring over medium heat, until sauce is thickened and comes to a boil. Drain onions and serve with sauce .