Spray a grill pan with olive oil and heat over medium- high heat until hot but not smoking. Place the bread slices on the grill and grill until grill marks appear on both sides, about two minutes per side.
Meanwhile, in a small bowl, place the mustard and honey. Stir with a small spoon until well combined.
Place the grilled bread on a work surface and spread the mustard and honey mixture on both slices. On one slice of bread, place the ham, gently folding each slice in thirds to give the sandwich some height.
Arrange the cheese slices on top and then the apple slices. Grind some black pepper on the apple.
Place the other slice of grilled bread on top. Slice the sandwich in half. Serve.