Pat the duck breasts dry with paper towels.

Using a sharp knife, score the skin in a crosshatch pattern, being careful not to cut into the meat.

Season both sides with salt.

Preheat the air fryer to 400°F (200°C) for 3 minutes.

Place the duck breasts skin-side up in the air fryer basket.

Cook at 400°F (200°C) for 10 minutes.

Reduce the temperature to 350°F (175°C) and cook for an additional 5 minutes, or until the internal temperature reaches 135°F (57°C) for medium-rare.

Remove the duck breasts from the air fryer and let them rest for 5 minutes.

In a small saucepan over medium heat, melt the unsalted butter, allowing the flavors to infuse for 2 minutes.

Slice the duck breasts thinly against the grain.

Drizzle the infused butter over the slices and serve immediately.