In a medium sized bowl, mix together all purpose flour and baking soda. Set aside.
In another bowl, mix together softened butter and peanut butter. It may help to use an electric mixer. Add sugars and mix until well combined.
Next, add the egg and milk. Mix well to combine.
Slowly add the flour mixture in small increments. Mix until just combined. Do not overmix.
Roll about a tablespoon of cookie dough into a ball. Use a fork to flatten the cookie. Place cookies into air fryer basket or onto air fryer tray.
Air fry the cookies for 6 to 7 minutes at 350 degrees F or 180 degrees C.
Remove cookies from air fryer. Cookies should rest until completely cool to strengthen. Enjoy!
Notes
Tip: If the dough is dry, add 1 to 2 more tablespoons of milk until desired consistency reached.Pro Tip: This recipe can be made in the air fryer unit with a basket or the air fryer oven. If you are using the air fryer oven, use the middle rack and select the "Air Fry" function.