Peel, core, and chop the apples into small, even-sized pieces. This ensures they cook evenly in the air fryer.
Place the chopped apples in an oven-safe bowl. Add a small amount of water (about 1/4 cup) to help steam the apples. Season with lemon juice, brown sugar and ground cinnamon. Set the bowl into the air fryer basket, cover tightly with foil. Set the air fryer temperature to 375 degrees F (190°C) and set cook time for 15-20 minutes, shaking the basket or stirring the apples halfway through to ensure even cooking.
The apples should be tender and easily mashable. If they are not tender enough, cook for an additional 5 minutes.
Transfer the cooked apples to a bowl. Use a fork, potato masher, or immersion blender to mash the apples to your desired consistency. For a smoother applesauce, blend until completely smooth.
Stir in additional cinnamon, granulated sugar, or brown sugar. Adjust the seasoning to taste.
Allow the applesauce to cool to room temperature before transferring it to an airtight container. Store in the refrigerator for up to a week or freeze for longer storage.