Heat the oven to 375°F. Lightly grease 8 cups of a standard muffin pan.
In a large bowl, combine the ground pork, breadcrumbs, egg, diced onion, milk, Dijon mustard, salt, pepper, and 1 tablespoon of the maple syrup. Mix gently until just combined.
Divide the pork mixture among the 8 prepared muffin cups. Press it in lightly without packing it too firmly.
Stir the remaining 2 tablespoons of maple syrup with the ketchup in a small bowl. Brush the mixture over the tops of the pork muffins.
Bake until the muffins are cooked through and reach 160°F in the center, about 20 to 25 minutes. Let them rest in the pan for 5 minutes before carefully removing them.
While the muffins bake, toss the apple matchsticks and shredded cabbage with the mayonnaise and apple cider vinegar. Serve the slaw alongside the warm meatloaf muffins.