Place diced bacon in a large sauté pan on medium low meat. Once some of the fat as been rendered out of the bacon add shallots and start caramelizing.
Occasionally stir shallots and bacon. Make sure to scrap any caramelization off the bottom on the sauté pan.
Sauté for 15 minutes until bacon is crisp and shallots are nicely caramelized.
Deglaze pan with balsamic vinegar and reduce until vinegar reduces to a syrup like consistency. Approximately 5 minutes.
This can be made 1-2 days in advance and will last 1 week in refrigerator.