Butter one side of each bread slice, then spread Dijon on the unbuttered side.
Top one slice with half the cheddar, then a single overlapping layer of apple slices.
Sprinkle with sage and black pepper, then drizzle with honey.
Add the remaining cheddar and close with the second slice, buttered-side out.
Cook in a skillet over medium-low heat, 3–4 minutes per side, pressing gently, until deeply golden and the cheese is fully melted.
Rest 1 minute before slicing. Enjoy!
Video
Notes
Leave the red peel on the apple for texture and color; peeling isn't necessary.
Cook low and slow (medium-low) so the cheese fully melts before the bread over-browns.
The thin layer of Dijon is the not-so-secret trick, don't skip it.
Storage: best eaten fresh! If needed, wrap tightly and refrigerate up to 2 days; reheat in a skillet over low heat to re-crisp (microwaving will make the bread soggy).