Preheat oven to 475°.
Bring water to a boil in a stockpot. Add onions; cook 30 seconds. Drain; cool. Peel onions; arrange in a single layer on a jelly roll pan. Top with 4 rosemary sprigs.
Combine wine and next 4 ingredients (wine through honey), stirring with a whisk. Pour wine mixture over onions. Bake at 475° for 30 minutes, turning twice.
Remove onions from pan with a slotted spoon. Carefully pour cooking liquid into a small saucepan; bring to a boil. Reduce heat; simmer 3 minutes or until mixture is the consistency of a thin syrup. Pour over onions; toss well to coat. Garnish with rosemary sprigs, if desired.