01 -
Preheat oven to 375 degrees Fahrenheit.
02 -
In a medium bowl, combine ground beef, egg, mustard, BBQ sauce, garlic powder, black pepper, and minced onion, except for bread crumbs.
03 -
Add bread crumbs to the mixture and mix thoroughly until well combined.
04 -
Shape mixture into an oval loaf and place it in a 4x8-inch baking pan.
05 -
Top the meatloaf with additional BBQ sauce, cover the pan with foil, and bake for 45 minutes or until fully cooked.
06 -
Remove meatloaf from the oven and transfer it to a plate. Let it rest for 20 minutes.
07 -
Slice the meatloaf into ¾-inch thick slices.
08 -
Butter one side of each slice of bread. Place one slice of bread buttered side down into a large frying pan or skillet over medium heat. Add a slice of pepper jack cheese, followed by meatloaf slices to cover the bread, then another slice of cheese, and top with a second piece of bread, buttered side up.
09 -
Cook until the bread is toasted, then flip the sandwich and toast the other side.