Step 1
Take the gammon joint out of the refrigerator approximately 45 minutes before you plan to begin cooking. In a small bowl, combine the Dijon mustard and honey or maple syrup, seasoning the mixture with salt and freshly ground black pepper. Evenly coat the gammon with the prepared glaze, reserving any excess. Wrap the gammon securely in foil.
Step 2
Preheat the air-fryer to 160°C. Place the foil-wrapped gammon inside and cook for 1 hour, basting with the reserved glaze every 20 minutes if possible. The gammon is ready when a digital thermometer inserted into the thickest part registers 70°C. Once cooked, remove the gammon from the air-fryer and allow it to rest for 10-15 minutes before carving. (Ensure the foil is crumpled into a ball before adding it to household recycling.)
Step 3
To assemble a sandwich, slice the gammon into thin pieces. Spread butter on one slice of bread, then add 1-2 tablespoons of pineapple salsa if desired. Arrange the gammon slices on top and cover with another slice of bread. Serve immediately.