Prep the air fryer: Preheat to 380°F (193°C) for 3–5 minutes. Lightly mist the basket with cooking spray if sticking is an issue.
Mix the glaze: Combine brown sugar, mustard, maple syrup (or honey), and vinegar (or pineapple juice).
Stir in a pinch of black pepper and any optional spices you like.
Pat the ham dry: Use paper towels to remove excess moisture. This helps the glaze stick and encourages light caramelization.
Coat the slices: Brush one side of each ham slice with the glaze. You’ll add more later, so don’t worry about full coverage yet.
Air fry the first side: Arrange slices in a single layer with space between them.
Cook for 3 minutes.
Flip and glaze again: Turn the slices, brush with more glaze, and cook 2–4 more minutes until edges are slightly crisp and the glaze is glossy.
Check doneness: The ham is already fully cooked, so you’re looking for heat and caramelization. Thicker slices may need another 1–2 minutes.
Rest and serve: Let the slices sit for 1 minute to set the glaze. Finish with a light crack of pepper and serve.