Preheat the oven to 350 degrees F. Coat a loaf pan with cooking spray.
Melt the butter in a medium saute pan and add the onions and 1/4 teaspoon of the salt. Sweat the onions, and then add the garlic and continue to cook. Stir in the chipotle powder and paprika and lightly toast with the onion mixture. Remove from the heat and let cool slightly.
Meanwhile, soak the bread in the milk until completely soft and hydrated. Squeeze out the excess milk and transfer to a large bowl along with the onion mixture, chuck, bacon, parsley, black pepper, eggs and remaining salt. Mix together.
Pack this mixture into a loaf pan and bake for 1 hour. Let cool slightly (it will be easier to slice).
Slice the meatloaf and serve it with your favorite mashed potatoes or potato salad.
This meatloaf also makes for a great late night snack, as well as a cold sandwich!