Melt the butter in a skillet over a medium heat. Add the diced pancetta and cook through until golden. Set aside to cool.
Whilst the pancetta is cooking, add the cream cheese, mozzarella, parmesan, ground almonds, salt and pepper to a mixing bowl. Finely chop the chives and add to the bowl. Beat together until well combined.
Add the cooked pancetta to the mixing bowl. Stir well to combine, distributing the pancetta evenly throughout the cheese mixture. Set to one side whilst you prepare the mushrooms.
Wipe the mushrooms clean. Remove and discard the stalks. Take a teaspoon and carefully run it around the inside of the mushroom to remove the gills.
Divide the cream cheese and pancetta mixture evenly between the two prepared mushrooms. Lightly grease the air fryer basket base with a little olive oil to prevent sticking. Brush the mushrooms with the remaining oil. Arrange the mushrooms side by side in the prepared air fryer basket.
Place the basket in the air fryer and set the temperature to 400 degrees. Set a timer for 12 minutes. After this time, check the mushrooms to see if they are tender and cooked through. Return them to the air fryer for a few minutes more if required. The mushrooms should be soft, piping hot through and the cheese should be golden. Serve hot.