In a small bowl, combine the melted butter, brown sugar, vanilla extract, and cinnamon to make the glaze.
Cut the peaches in half (along their spine) and twist the halves to remove them from the pit.
Brush the glaze over each of the cut peach halves, letting it pool in the center of the peach.
Place the peach halves in the basket of an air fryer (it does not need to be preheated).
Air fry at 350°F for 12-15 minutes, basting with more glaze halfway through.
Once the tops of the peaches look caramelized and are soft, remove them from the basket and place them on individual plates. Brush them with more glaze and sprinkle the crushed pistachios on top.
Serve the peaches while still warm, topping with vanilla ice cream, additional crushed pistachios and drizzle of glaze, if desired.