Rinse and dry apples with paper towels. Peel skin and then dice apples into small bites. Combine apples and lemon juice in a medium bowl and set aside.

In a separate bowl, combine the melted butter, brown sugar, old fashioned oats, all purpose flour, and ground cinnamon. Stir ingredients together until it becomes a crumble. Set bowl aside.

Lightly spray non-stick cooking spray on the insides of your small ramekins. Spoon apple mixture equally into the individual ramekins.

Air fry at 300 degrees F for 8-10 minutes, until apples are cooked through and tender. You can check using a fork to make sure apples are softened.

Spoon oat topping mixture over the apples, and then return basket to the air fryer. Air fry at 300 degrees F for an additional 3-5 minutes, until oatmeal topping is golden brown and slightly crispy.