Balsamic–Caramelized Onion Bread

This bread is the brainchild of my tester, Mary Anne McCready. This was her favorite method of preparing onions, and they ended up in and on everything, from vegetables to roasts. It was only a matter of time before they ended up in her bread. The slow cooking of the onions with the balsamic vinegar makes for a very sweet vegetable addition to a savory bread. While the bread is baking, be prepared to suffer as its tantalizing smell fills the kitchen. This bread is very aromatic with vinegar