1 Put the butter for some extra creaminess and brown sugar for sweetness in bowl and whisk together until light and fluffy using an electric hand whisk. Add the egg and vanilla extract for warmth, then whisk until combined. Sift over the plain flour and baking powder. Stir with a wooden spoon until combined. Stir through the dark chocolate chips for extra richness to the dish.
2 Roll the cookie dough into approximately 18-20 golf-sized balls – it will be a little sticky but this is fine. Line the air –fryer basket with baking parchment. Working in batches, flatten 3-4 cookie dough balls into slim patties between your hands. Place in the air fryer basket allowing plenty of room for the cookies to spread. Set the air fryer to 180ºC and cook for 5-6 mins until the edges are just firm.
3 Allow the cookies to cool and firm-up a little in the air-fryer for a few minutes, then carefully remove using an angled spatula and transfer to a wire rack to cool completely. Repeat with the remaining dough balls.