Combine all ingredients in a bowl with a spoon, hand mixer, or stand mixer.
The dough should be stiff enough to roll, but if needed you can add more water, 1 tablespoon at a time if the batter is too thick.
Roll the dough into small balls or scoop with a cookie scoop and place them in a parchment-lined air fryer basket. You will need to work in batches.
Air fry for 4-6 minutes at 350 degrees F or 180 degrees C. The cookies should be firm on the sides and soft in the middle, but not gooey. For firmer cookies, bake 2-3 minutes longer.
Cookies should be firm on the sides and slightly chewy in the middle but fully set. You do not want them gooey. You can also cook them for 2-3 minutes longer for firmer cookies.
Allow the cookies to cool for 3-4 minutes in the basket and then transfer to a cooling rack.
Repeat the process until all the cookies are made.
Oven Instructions
Preheat the oven to 375 degrees F or 190 degrees C. Combine all ingredients in a bowl with a spoon, hand mixer, or stand mixer.
While the dough should be stiff enough to roll, If you find your batter is too thick, add more water, about 1 tablespoon at a time.
Roll the dough into small balls or scoop with a cookie scoop and place on a parchment-lined baking tray.
Bake for 8-9 minutes at 375 degrees F / 190 degrees C or until just cracking on top.
Cookies should be firm on the sides and slightly chewy in the middle but fully set. You do not want them gooey. You can also cook them for 2-3 minutes longer for firmer cookies.
Allow the cookies to cool for 3-4 minutes on the tray and transfer to a cooling rack.
Video
Notes
Different brownie mixes may produce slightly different results.
Dough too wet? Add a tablespoon of flour at a time until it reaches the right consistency.
If the dough is too dry, add a tablespoon of water at a time to get the right consistency.
Place parchment or a silicone mat in the air fryer basket then add cookie dough.
Use a cookie scoop to create uniform-sized cookies.
Leave space between the cookies as they spread slightly as they bake.
Since air fryer temperatures can vary, watch cookies closely the first time you make them (you don't overcook) and adjust the cooking time as needed.
Storage - keep cookies in an airtight container on the counter for up to a week.