Mix burger sauce ingredients together and refrigerate to develop flavors. Taste and adjust salt and pepper to preference.
Dice the beef bacon and cook in a heavy bottom pan over medium high heat for 10-15 minutes until mostly crispy and cooked through. Remove and set aside to drain.
Remove all but 1 tbsp of bacon grease from the pan. Add diced white onion and sauté for 3-5 minutes.
Add black coffee, maple syrup, and brown sugar to the pan. Stir to combine and bring to a simmer over medium low heat.
Add the cooked beef bacon back into the pan and simmer for 40-45 minutes until thickened and jammy. Add beef stock if needed for extra liquid.
Make the smashburgers according to preferred method.
Assemble burgers by spreading burger sauce on toasted buns, adding pickles, placing smashburger patties, and topping with bacon jam. Add more sauce to the top bun and serve.
