In a medium saucepan, cook bacon over medium heat until crispy.
Place cooked bacon on a plate lined with a paper towel. Break the bacon into about 1-inch pieces to be added later.
You need about 4 tablespoons of bacon fat to remain in the pan, carefully remove the rest. (It is hot! We store it in mason jars.)
Add the onion and diced shallots to the pan with the bacon grease, reducing heat to medium-low. Cook until the onions are caramelized (about 15-20 minutes), stirring often.
Mix in the garlic, brown sugar, maple syrup, apple cider vinegar, chili powder, and pieces of cooked bacon.
Simmer for 7-10 minutes, or until the mixture has thickened. (Think of the consistency of a jam.)
Serve warm or cold, but you may want to warm slightly if it has been refrigerated.