The best Air fryer cookie for one (easy recipe)

0 In a small bowl, cream together the softened butter, sugar, and vanilla extract until fully mixed. You can use a handheld whisk or a fork.
1 Add the egg yolk and mix until just combined.
2 Add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the chocolate chips. Be careful not to overmix the cookie dough, which could result in a tougher cookie after baking.
3 Shape the dough into a ball with your hands, then gently push it to shape it as a disk. If the dough is too soft or sticky, place it in the fridge for a few minutes until easy to handle.
4 Preheat the air-fryer to 325 F in the bake setting. Place the cookie dough disk on top of a 7x7 inch greased aluminum foil or specially designed air-fryer parchment paper, and place it in the air-fryer basket. 
5 Air fry for 7-9 minutes (keep an eye on it, every kind of air fryer is different and times may change) or until edges are golden brown and the center is still soft. The cookie will firm up as it cools. Remember that the cookie continues to cook slightly after it is out of the air fryer.
6 Let cool completely and enjoy with a scoop of vanilla ice cream.