Cut bacon into 1-inch pieces. In a large sauce pan, cook bacon over medium heat until crispy. Remove bacon bits from the pan leaving the bacon grease behind.
Turn heat down to low and add in onions. Cook low and slow for 30 minutes until golden brown.
Add in remaining ingredients and bring to a simmer.
Continue to cook until reduced and sauce is thickened.
Allow to cool completely and store in refrigerator.